Tuesday, November 27, 2018

Lesson 6-7: Corresponding Parts in Congruent Figures (Day 67)

Today I subbed for a high school P.E. class. Needless to say, this is unrepresentative of the class that I'd like to teach someday, and thus there's no "Day in the Life" today.

All periods are freshman P.E. classes. But some classes play basketball in the gym (if it's available) while others -- fourth period -- walk a mile on the track.

It's tough naming a best class of the day. In fourth period, I tell the students to stay ahead of me while I walk with them at a slow 6:00 per lap (24:00 for the mile) pace, but ten students nonetheless fail to stay ahead of me (and I was only able to figure out half of their names). So I recommend that the teacher deduct their two daily participation points (or one, since they did finish the mile).

So in sixth period, I tell them that I'll recommend a detention in addition to the minus two points, and this time, all of them finish well ahead of me. But then they're so far ahead of me that they start dressing early and leaving the P.E. area before the dismissal bell (as much as 10-11 minutes early). I inform another P.E. teacher, and she says that it was OK for them to leave. (Still, I bet she was thinking about five minutes early, not ten.)

Thus we have a trade-off. Fourth period doesn't leave early because they walk too slow. Sixth period walks faster, but so fast that they want to leave early. In the end, I name sixth period the best walking class of the day (since the other teacher did say it was all right to leave).

So that leaves the basketball classes. In the morning classes there were some nonparticipants. In fifth period, I push them more to avoid sitting down or using a phone instead of basketball (probably because the fourth period mess is still fresh in my mind). The fifth period students enjoyed hoops -- so much, indeed, that they refused to put the balls back at the end of class. Instead, they just keep saying "One more shot!" and shooting -- then someone else rebounds and it repeats.

Therefore once again we have a trade-off. Third period cleans up faster because they're unenthusiastic about playing. Fifth period has more participation, but then they don't clean up the gym. In this case, I inform the teacher that either class can be considered the best basketball class of the day -- third period has the best behavior (especially at the end of class) but fifth period has the most participation.

Today there is a Google Doodle for Fe del Mundo, a famous pediatrician from the Philippines. I like to highlight STEM Doodles on the blog, but it's debatable whether medicine counts as STEM. Well, since the following link is called "Grandma Got STEM" and the authir chose to write about Fe del Mundo (three years ago), I suppose that this does count as STEM:

https://ggstem.wordpress.com/2015/10/15/fe-del-mundo/

That page in turn links to the following article:

http://www.amazingwomeninhistory.com/fe-del-mundo-first-female-student-at-harvard-medical-school/

I found that article interesting -- del Mundo was only admitted to Harvard Medical School because officials thought that she was a man! (Imagine if her first name had been "Faye" instead of "Fe.")

By the way, seeing an Asian woman like del Mundo being admitted to Harvard reminds me of the recent debate regarding Asian-Americans applying to Harvard. Apparently, many of them have been rejected due to their "personality" in favor of other minority students.

This isn't a holiday post (and actually I meant to bring this up over Thanksgiving, but I didn't). But I'm actually curious as to the opinion of someone like Eugenia Cheng. (Yes, I did warn you that I'll mention her name in debates of this type.) On one hand, we know that Cheng cares deeply about underrepresented minorities and would want them to have the opportunity to study at Harvard and other Ivy League schools. On the other hand, Cheng is of Asian descent, and I doubt that she'd want someone to criticize her personality just because she's Asian.

So far, I haven't seen Cheng comment on Harvard admissions, but for the reasons above, I definitely will respect her opinion on the matter.

Lesson 6-7 of the U of Chicago text covers the Corresponding Parts in Congruent Figures Theorem, which the text abbreviates as CPCF. But a special case of this theorem is more widely known -- corresponding parts in congruent triangles are congruent, or CPCTC.

This is what I wrote last year about today's lesson:

When I was young, a local PBS station aired a show called Homework Hotline. After school, middle and high school students would call in their homework questions in math and English, and some would be chosen to have their questions answered on the air by special teachers. Even when I was in elementary school, I often followed the geometry proofs that were called in, and more often than not, there were triangle congruence two-column proofs where the Reason for a step was often CPCTC. So this was where I saw the abbreviation CPCTC for the first time. (By the time I reached high school, a few calculus problems were called in to the show. Nowadays, with the advent of the Internet, the show has become obsolete.)

Here's a link to an old LA Times article about Homework Hotline:

http://articles.latimes.com/1992-02-09/news/tv-3184_1_homework-hotline

When I reached geometry, our text usually either wrote out "corresponding parts in congruent triangles are congruent," or abbreviated as "corr. parts of cong. tri. are cong.," probably with a symbol for congruent and possibly for triangle as well. But our teacher used the abbreviation CPCTC. Now most texts use the abbreviation CPCTC -- except the U of Chicago, that is. It's the only text where I see the abbreviation CPCF instead.

Dr. Franklin Mason, meanwhile, has changed his online text several times. In his latest version, Dr. M uses the abbreviation CPCTE, "corresponding parts of congruent triangles are equal."

Well, I'm going to use CPCTC in my worksheets, despite their being based on a text that uses the abbreviation CPCF instead, because CPCTC is so well known.

Once again, it all goes back to what is most easily understood by the students. Using CPCTC would confuse students if they often had to prove congruence of figures other than triangles. But as we all know, in practice the vast majority of figures to be proved congruent are triangles. In this case, using CPCF is far more confusing. Why should students had to learn the abbreviation CPCF -- especially if they have already seen CPCTC before (possibly by transferring from another class that uses a text with CPCTC, or possibly even in the eighth grade math course) -- for the sole purpose of proving the congruence of non-triangles, which they'd rarely do anyway?

So it's settled. On my worksheet, I only use CPCTC.

Notice that for many texts, CPCTC is a definition -- it's the meaning half of the old definition of congruent polygons (those having all segments and angles congruent). But for us, it's truly a theorem, as it follows from the fact that isometries preserve distance and angle measure.

Another issue that comes up is the definition of the word "corresponding." Notice that by using isometries, it's now plain what "corresponding" parts are. Corresponding parts are the preimage and image of some isometry. Unfortunately, we use the word "corresponding angles" to mean two different things in geometry. When two lines are cut by a transversal and, "corresponding angles" are congruent, the lines are parallel, but when two triangles are congruent, "corresponding angles" (and sides) are congruent as well. The phrase "corresponding angles" has two different meanings here! Of course, one could unify the two definitions by noting that the corresponding angles at a transversal are the preimage and image under some isometry. I tried this earlier, remember? It turns out that the necessary isometry is a translation. This is one of the reasons that I proved the Corresponding Angles Test using translations -- it now becomes obvious what "corresponding angles" really are. I mentioned yesterday, however, that in many ways using translations to prove Corresponding Angles is a bit awkward since it took so much work to avoid circularity. (This is why some authors, like Dr. Hung-Hsi Wu, uses rotations to prove Alternate Interior Angles instead.)

Just before Thanksgiving, I wrote about how many teachers often given multi-day activities, but I've never done so on the blog. And so today I post such an activity:

Monday: Lesson 6-6 (Day 66)
Tuesday: Lesson 6-7 and Begin Multi-Day Activity (Day 67)
Wednesday: Finish Multi-Day Activity (Day 68)
Thursday: Review for Chapter 6 Test
Friday: Chapter 6 Test

This activity is based on the Exploration Question in today's text:

a. Find three characteristics that make Figure I not congruent to Figure II.
b. Make up a puzzle like the one in part a, or find such a puzzle in a newspaper or magazine.

Students can perform part a today and part b ("Make up a puzzle") tomorrow. Of course, if they wish, they can do the "find such a puzzle" part tonight. With this plan, we return to having only one day for review -- a formal test review to be given on Thursday.

The following worksheet comes from the website:

[2018 update: This page is no longer accessible. I'm glad that I got it before it disappeared!]

Monday, November 26, 2018

Lesson 6-6: Isometries (Day 66)

Today is Cyber Monday. So of course, I had to order something on Amazon today -- and that something is the Pappas Mathematical Calendar for 2019.

Meanwhile, it's come to my attention that November 23rd wasn't just Black Friday -- it was also Fibonacci Day, because the digits of the date were 1, 1, 2, 3. Unfortunately, Fibonacci Day fell on a day when I didn't post.

Here's a link to a Fibonacci Day post:

http://bedtimemath.org/fun-math-fibonacci-day/

The fact that Fibonacci Day is always close to Thanksgiving causes a problem if we wish to celebrate the day in schools. Indeed, in districts that take the entire week off for Turkey Day (which includes both of my districts), schools are closed on November 23rd 100% of the time. It's one of the four days in November when schools are never open -- the others are the 24th, 25th, and 11th (Veteran's Day).

In districts that are open Monday, Tuesday, or Wednesday before Thanksgiving, then Fibonacci Day is a school day provided it falls on one of those days. This will next occur in 2020-2022 -- and a Fibonacci Day activity might be something nice to do in the week leading up to Thanksgiving.

If we really want to observe a Fibonacci Day at school, then there are other ways to use Fibonacci digits to form a date. Indeed, Laura Overdeck, at the above link, mentions the following dates:

The sky’s the limit: 10 dates: 1/1, 1/2, 1/12, 1/23, 2/3, 3/5, 5/8, 11/2, 11/23, and 12/3.

(She could have also listed 8/13, since 13 is the next Fibonacci after 8.) Of these, January 23rd, February 3rd, March 5th, May 8th, November 2nd, and December 3rd are far enough anyway from long school vacation periods to be suitable Fibonacci Days.

According to Overdeck, we're 40 years away from Fibonacci Day of the Century, 11/23/58. It's also possible to make some of her other ten dates into possible Fibonacci Days of the Century -- for example, 5/8/13, since 5 + 8 = 13. This is acknowledged at the following link:

https://www.treehugger.com/natural-sciences/its-5813-or-fibonacci-day-america.html

Lloyd Alter, the author of this article, also looks forward to 8/13/21, the next such possible Fibonacci Day of the Century. This is less than three years away (though it's likely to be slightly before the first day of school in most districts).

Finally, here's a link to Anna Pacura, a New York middle school teacher. In 2015, Fibonacci Day fell on a Monday and her school was open, so she had a Fibonacci lesson:

http://iamamathteacher.blogspot.com/2015/11/fibonacci-day-zero-socratic-seminar.html

She alludes to her 2016 Fibonacci Day lesson in the following post. This is the same year that I worked at the old charter school and just like me, Pacura taught all three middle school grades. But again, her school was open the day before Thanksgiving, while I took that whole week off:

http://iamamathteacher.blogspot.com/2016/11/almost-thanksgiving-break.html

(That's right -- during that year I linked to Pacura as an example of a middle school math blog.)

Lesson 6-6 of the U of Chicago text is called "Isometries." In the modern Third Edition, we must backtrack to Lesson 4-7 to learn about isometries.

This is what I wrote last year about today's lesson:

What, exactly, is a glide reflection? Well, here's how the U of Chicago defines it:

Let r be the reflection in line m and T be any translation with nonzero magnitude and direction parallel to m. Then G, the composite of T and r, is a glide reflection.

Just as reflections, rotations, and translations have nicknames -- "flips," "slides," and "turns," respectively -- glide reflections have the nickname "walks." The U of Chicago gives the example of the isometry mapping the right footprint to the left footprint while walking as a glide reflection. Another name for glide reflection is "transflection," since it is the composite of a reflection and a translation.

I once tutored a geometry student who had a worksheet on glide reflections. The student had to use a coordinate plane to perform the glide reflections, which were given as the composite of a reflection and a translation. But the problem was that on the worksheet, the direction of the translation wasn't always parallel to the reflecting line! In fact, in one of the problems the translation was perpendicular to the reflecting line. That would mean that the resulting composite wasn't truly a glide reflection at all, but just a mere reflection!


Saturday, November 24, 2018

Small Business Saturday Post

Table of Contents

1. Pappas Question of the Day
2. Small Business State Meet Saturday
3. Starting Line: Freshman Year
4. Mile 1: Sophomore Year
5. Mile 2: Junior Year
6. Finish Line: Senior Year
7. Cross Country and Academics
8. McFarland USA
9. McFarland's XC Team -- and My Team -- Now
10. Conclusion

Pappas Question of the Day

Today on her Mathematics Calendar 2018, Theoni Pappas writes:

The area of ABCD = ?

(Here is the given info from the diagram: AB = 5', BC = 6', CD = 3', Angles C, D are right angles, AD unknown but it's clear that AD > BC.)

Notice that Quadrilateral ABCD is a (right) trapezoid. To find the area of a trapezoid, we need its height and two bases. The height is CD = 3 (the height because of the right angles) and one of its bases is BC = 6. But we don't know the length of the other base AD.

Let's drop a perpendicular from B to AD and label the foot of the perpendicular E. Then BCDE is a rectangle, with ED = BC = 6 and BE = CD = 3. So ABE is a right triangle with leg 3 and hypotenuse 5, and then it's easy to find AE, the other leg using the Pythagorean Theorem:

a^2 + b^2 = c^2
BE^2 + AE^2 = AB^2
3^2 + AE^2 = 5^2
9 + AE^2 = 25
AE^2 = 16
AE = 4

And AD = AE + ED = 4 + 6 = 10, so we finally have the length of the other base. Now we can use the trapezoid area formula:

A = (1/2)h(b_1 + b_2)
A = (1/2)(CD)(BC + AD)
A = (1/2)(3)(6 + 10)
A = 24

Therefore the area of Trapezoid ABCD is 24 square feet -- and of course, today's date is the 24th.

The trapezoid area formula appears in Lesson 8-6 of the U of Chicago text. But this problem can't be solved until after the following lesson, Lesson 8-7. This is because the Pythagorean Theorem is needed to find one base of the right trapezoid.

Small Business State Meet Saturday

Today is Small Business Saturday, the day after Black Friday and two days after Thanksgiving. It was created by American Express in order to encourage Christmas shopping at local stores. It can be shown that "Saturday after Thanksgiving" is equivalent to "last Saturday in November," which makes the date easy to find on a calendar.

But Small Business Saturday has only existed since the start of the decade. To me, the Saturday after Thanksgiving has had another meaning -- the day of the California State Cross Country Meet. This is a race of about three miles (actually five kilometers) in length.

I've mentioned my career as a high school distance runner several times on the blog (most recently on Halloween and All Saints Day, when I spoke to the XC runner in the class I subbed for). Therefore, I'll devote today's post to a full discussion of my cross country career. After all, it's still Thanksgiving break as well as State Meet Saturday.

But first, let me point out the significance of the date. The State Meet was always held the Saturday after Thanksgiving. In fact, the dates of all the races can be determined by counting backwards from State Meet Saturday (or Thanksgiving). On the other hand, the dates of the first day of school, the second semester, and the last day of school are determined at many schools by counting forward from Labor Day, not Thanksgiving.

For example, here were some key dates from my own days as a XC runner:

  • First race of the season: 12 Saturdays before State Meet (first Saturday in September)
  • Last dual meet of season: 4 Thursdays before Thanksgiving (last Thursday in October)
  • League Finals: 3 Thursdays before Thanksgiving (first Thursday in November)
  • Section Finals: Saturday before Thanksgiving (penultimate Saturday in November)
  • State Meet: Saturday after Thanksgiving (last Saturday in November)
Since then, some of these dates have changed. For example, there's now a tendency for dual meets in many leagues (including my own) to be held on Wednesdays, not Thursdays. The first race of the season is also now a week earlier (the last Saturday in August). But the State Meet hasn't changed.

In other high school sports, such as football, the dates have changed dramatically -- the season starts nearly a month earlier now than my own high school days. This is mainly so that there's enough time to hold the state finals comfortably before Christmas. (In my days, there were no state football finals.)

Football season now begins 14 weeks before Thanksgiving (in mid-August). The season itself is 11 weeks long (enough for ten games and a bye week). In November, four rounds of sectional playoffs take place (at least here in the Southern Section -- the state's largest section). The first round is three weeks before Thanksgiving and the last round is this weekend. Last night, a sectional finals game took place between arguably the top two teams in the nation -- Mater Dei and St. John Bosco. (In the end, Mater Dei upset Bosco 17-13.) Then there are two weeks for state semifinals and state finals.

I often wondered why the new football schedule would take effect this year, when Thanksgiving falls on its earliest possible date (November 22nd). It would have been less a shock for players and coaches had the transition occurred next year, when Turkey Day is as late as possible (the 28th).

But the extra week turns out to be beneficial this year -- due to the California wildfires, many playoff games were cancelled. The state finals were pushed back a week, to December 14th-15th. So starting the season early allows some leeway if a game needs to be cancelled (for wildfires or any other reason) and still allow the state finals to be played before Christmas.

That's enough about football -- let's get back to my sport, cross country. Actually, I've read that some cross country races were also cancelled, including the Los Angeles Section Prelims. (That's right -- the LAUSD, as well as charters within LAUSD, aren't part of the Southern Section but are placed in their own City Section.) Instead, all LA City teams proceeded directly to the section finals.

In today's post, I wish to tell you the story of how I became a high school cross country runner.

Starting Line: Freshman Year

I admit that growing up, I'd never thought of myself as an athlete, much less a distance runner. I've heard that I had a slender frame -- a runner's body. But still, running races wasn't something that I had an urge to do. For most sports, I was often the proverbial "last person picked."

I remember one day in seventh grade, when the P.E. teacher had all students compete in two races on the track -- 200 meters and 400 meters. After the races, she told the first few runners in each race to stand up and be acknowledged. I was one of the top runners in the 400, but not the 200. As I stood up, another student -- one of the top 200 runners -- remarked that we weren't the fastest runners. In a way, he was right -- the 200 is a pure sprint. The 400, while not exactly a distance race, nonetheless isn't a pure sprint either. Speed matters, but endurance starts to make a difference too. The other guy had the speed, but lacked the endurance to keep up with runners like me in the long sprint.

Throughout middle school P.E., we occasionally had to do a mile run on the track. I remember one such four-lap run in eighth grade. After the first lap I was ahead of all my classmates. After the second and third laps I was in second place. I finished the race in third place. If I recall correctly, my time was just under eight minutes, good enough for an "A" in the mile run. (Ten minutes was a "B," twelve minutes was a "C," and any time over twelve was a "D" provided a full mile was completed.)

Early the following summer, I received a letter. It was from the coach of a sport that I had never heard of -- cross-country running. He was inviting me to join the team. At first I was intimidated -- three miles sounded like such a long distance. But then I reminded myself that I had a runner's body, and I was unlikely to be successful in any other sport. And so I joined the team.

On the first day of practice, the coach told me to run three miles on the track. Then he led the rest of the team on a "short" distance run to the mall and back -- a round trip of just over four miles. I completed the dozen laps on the track, but I had to stop and rest several times.

Summer practices were held thrice a week. Mondays were for long road runs, while Wednesdays were for intervals on the track. Other types of workouts were held on Thursdays. At the end of each summer workout, the coach would give us all sodas.

One memorable workout occurred on Monday, August 14th. For the workout, the coach had planned an eight-mile road run -- four miles out, four miles back. For the first three miles, I tried to keep up with my more experienced teammates. We managed to catch every green light until we reached the three-mile mark. It was the first time that I'd ever run the length of a XC race without stopping -- though it took me about a half-hour.

I stopped to catch my breath, while the rest of the team continued to run. I decided that since I was still a novice runner, I wouldn't be able to complete the full eight-mile workout. Typically, the coach would have us run the return part of each workout along the side of the "river" (which here in Southern California really means something like "flood control channel"). This way, we'd be able to avoid red lights and run the distance without stopping.

And so I ran three miles along the river bike path back to school. But for some reason, the gate leading from the river back to the street was locked. I'd either have to run an extra mile to the next street (and yet another mile to get back) and hope the gate was unlocked, or try to climb the fence. I was too tired even to climb the fence. Instead, I decided to take a shortcut directly across the river. I remind you that this isn't a real river (like the Mississippi) -- it's only a few feet across and only a few inches deep.

But the force of this river was powerful -- once I stepped in, it's impossible even to stand up! The river swept me several miles away from the school (and in the opposite direction from where my teammates were running). I was saved only because one person driving on a bridge spotted me -- and she just happened to have a cell phone. (This was in 1995, so cell phones were rare.) A fireman was summoned, and he intercepted me one mile farther down the river.

What should I have done? Either I should have simply climbed over the gate, or perhaps waited for the teammates running the extra two miles to catch up. (I'd already run to a second gate hoping it would be open, and there was no guarantee the others would have run past the second gate if they were already climbing over the first one.)

A few weeks later, the season began. The early-season schedule had us racing twice a week -- on Thursdays there would be a non-league dual meet (that is, a race against one other school that isn't in our league) and on Saturdays there were weekend invitationals against many schools. In my first Thursday meet my time for three miles was around the mid-24's, and in my second invitational nine days later, my time was in the mid-21's. The coach joked that if I could keep this up, I could run it nine minutes by the end of the season! (Of course, that would be a world record by fat.)

In reality, by the time the league dual meets began I didn't keep improving by a minute every race (no one can). But in my third invitational -- the huge Dana Hills Invitational -- I broke 21 minutes. That is to say, I ran under 21 minutes for the first time (I believe my time was 20:50).

This was the year that I moved from one school to another. As it turned out, the week of the move was the same week as League Finals, and so I didn't actually complete my freshman season.

At my new school, Cross Country season was over, but many runners move on to track. The distance races that most XC runners participated in are 800, 1600, and 3200 meters. (For those who don't know the conversion, 1600 meters is almost one mile.)

Mile 1: Sophomore Year

At my new school, the season schedule was a little different. The first race of the season was always a time trial (that is, we ran against the clock, not another school). It also marked the main fundraiser of the season -- tickets to a pancake breakfast. Also, there were no non-league dual meets -- the five league dual meets fell on the five Thursdays in October, followed by League Finals. The time trial as well as three of the league meets took place on our home course.

But I always had trouble filling out the athletic clearance papers in time for the start of the season. So instead, my first race of the season was the third Saturday. This is another huge invitational -- the Woodbridge Invitational. Held on that high school's campus, the Woodbridge race regularly produces our fastest times of the year. That day, I broke 20 minutes for the first time.

Another major race that we prepared for was the Mt. SAC Invitational. This race regularly takes place in mid-October, on the second Saturday before League Finals. The name Mt. SAC refers to a community college, but that word "Mt."/"Mount" gives away what the course was like. It's the hilliest XC course that we run on. During the weeks leading up to Mt. SAC, we would have "hill repeats," which are like intervals except they're run on a nearby hill. These workouts were often led by our two senior captains.

I never looked forward to hill repeats, or any hill workouts. But they're very helpful -- after running six, seven, eight miles on hills in practice, the three-mile Mt. SAC course was a cinch! Of course, my times at Mt. SAC were never as good as Woodbridge -- that year, my Mt. SAC time was mid-20's.

The following Thursday was the last dual meet of the season -- Halloween. That year, Thanksgiving fell on its latest possible date (the 28th) and so the last dual meet was four weeks earlier. It marked the only time I've ever raced on Halloween. (Nowadays, with league meets on Wednesdays, this year's early Thanksgiving leads to League Finals on Halloween.) The final dual meet was held on our home course, and that day I ran a few seconds slower than Woodbridge.

A week later was my first League Finals, held at a local park. That day I capped off the season with my third (or maybe fourth) sub-20 performance.

Mile 2: Junior Year

Once again, I wasn't cleared to run in races until Woodbridge. Once again, I set another PR, or personal record, as I broke 19 that day.

That year, our school had many fast runners. Some of our top runners were hoping to advance all the way to the State Meet. But only Varsity runners were allowed at postseason races. The Varsity team consisted of seven runners plus two alternates -- and our top nine runners all had sub-17 times.

Since my PR was just barely under 19 minutes, I had to run Junior Varsity, not Varsity. All juniors and seniors not on Varsity were relegated to the JV team. As it turns out, not many members of the Classes of 1998 and '99 had joined the cross country team -- and of the few who did, most of them ran Varsity.

Excluding the alternates, I was the only junior not on Varsity -- and for most of the season there was only one non-Varsity senior as well. This made running in JV races a lonely affair.

At the end of the season, our Varsity runners indeed ran in the postseason races. The section prelims and finals were both held at Mt. SAC -- and this underscores the importance of preparing for hilly courses and doing well at the Mt. SAC Invite. The state meet was held at Woodward Park in Fresno, where it's still held to this day. (Recall that Fresno is the one of the Central California cities that opposed Prop 7 and supports the biannual clock change.)

Meanwhile, my season ended at League Finals, which were held at a local university. At the end of the season, I received an award for the most improved JV runner -- but then again, there weren't that many JV runners in the first place.

Finish Line: Senior Year

For once, I was actually cleared in time for the opening time trial. If I recall correctly, my time was right around 19 minutes. At Woodbridge I set another personal best, but only by a few seconds as opposed to the huge PR's I'd set the previous two trips to this invite.

I knew from the start of the season that there was no way I'd make the Varsity team. Two seniors from the previous year had graduated, but two new freshmen had joined the team -- and they were already running under 16 minutes. (One was the younger brother of two other XC runners.) Of course, I wasn't named a senior captain either -- all four Varsity seniors became captains.

But this time, we had a full JV team. The incoming Class of 2000 juniors was a much larger class of runners, and only two of them ran Varsity. I actually end up finishing in first place at two of the JV dual meets held on our home course -- and my times continued to improve throughout the year. At the last dual meet, my time was just one second slower than my Woodbridge time.

League Finals were held at the same university as the previous year. I knew that it was my final XC race and so I wanted to run as fast as I could. Along the final stretch I couldn't help but stare at my stopwatch to make sure that I had a good time. My time for my final race was 17:43, which was good enough for fourth place. The winner was our alternate Varsity runner who finished exactly a minute ahead of me, and the only other JV senior (who had missed his junior year of XC) finished exactly a minute behind me.

It's now believed that the League Finals race was somewhat short of three miles. Using a conversion factor that we were given after the race, my time converts to 17:57 for three miles. Therefore I can still say that I'm a sub-18 runner. At the end of the season, I received an award for the most outstanding JV runner -- and this is less trivial since we had a full JV team.

I still consider breaking 18 minutes in XC to be one of my greatest personal accomplishments -- even when compared to my times on the track. I fell just short of breaking five minutes in the 1600. I suppose my goal for the 3200 was 11 minutes (in other words, 5:00/mile for one mile, 5:30/mile for two miles, and 6:00/mile for three miles), but I never came close. I think I only ran the 3200 once during my senior year -- and I believe that my fastest ever 3200 was actually the first two miles of the XC race held on our home course. Instead of the 3200, I often ran the 800 -- and I don't even recall much about my 800 times. (I believe my best time was about 2:20-ish.)

Cross Country is the One True Sport. Everything else is just a game.

Cross Country and Academics

Some sports -- especially football and basketball -- have a reputation for attracting students who aren't interested in academics. For players hoping to get into Division I colleges, it's often an uphill battle to remain academically eligible by earning good grades and high SAT scores.

But this isn't the case with Cross Country. It seems that most Cross Country runners have excellent academic records. Most of my teammates were part of our magnet program. I wasn't -- but only because most students apply for the magnet in eighth grade, while I was still attending another district at the time. (As I wrote earlier, I transferred in the middle of freshman year.) Two years later, I was finally admitted to the magnet program -- in fact, it happened on the very day of League Finals.

The magnet program is considered to be a year ahead of the regular program. Therefore as a junior, I attended English and history with the sophomores. Some of those students would become my JV teammates the following year.

I suspect the reason that XC runners, unlike football players, basketball players, or other athletes, do well in school is because XC runners are used to doing something difficult and boring (that is, running) for long periods of time. We're used to working hard, enduring, and being persistent as we strive towards a goal, a finish line, that might be far away. This isn't to say that other athletes don't work hard, but the difference is that they're used to getting quick, visible results. We XC runners are more likely to think in terms of the big picture.

That XC runners tend to excel academically is most noticeable when we take a look at the LA City Section Finals results. In both the boys and girls Division I races, the top school is Granada Hills -- a charter that's best known for winning national Academic Decathlon titles. Two of the other top teams are El Camino and Pacific Palisades -- other charters with strong academic programs. I doubt that any of the Granada Hills Varsity runners are also on the Academic Decathlon team. Instead, the rigorous academic environment invites both Academic Decathletes and distance runners (who again are used to working hard for long periods of time).

In my last post, I wrote about Floyd Thursby, who decries teachers who don't want to work the Tuesday before Thanksgiving. He once also wrote about the last week of school -- and how many schools have teachers turn in grades early, so the last week is wasted. Many students believe that they're entitled to a week of no academics at the end of the year anyway.

But that's not the XC way of thinking. Taking the last week off of school is like pulling up in a race before crossing the finish line. We need to run hard through the finish line -- and so likewise students need to work hard through the last day of school.

Senioritis wasn't in my mind when I was in the twelfth grade. I worked hard on the XC course throughout my senior year, and I believe that I'm one of the few seniors to PR in my final race. The other senior who won the JV race that day was a Varsity alternate, and so League Finals would not be his final race. (As an alternate, he did run at Section Prelims.) I was the rare non-Varsity senior who actually worked hard to improve my times my final year.

And in fact, I worked hard academically during my second semester of senior year. I'd never earned straight A's in a semester before, always ending up with at least one B (often in English). But I failed to reach my goal -- instead I ended up with all A's except for two B's, both in English. (The extra English class was required by the magnet since I was a year behind, as stated earlier.)

I want to encourage my students to think more like distance runners -- even if they never run more than a mile at a time. Just before I started working at the old charter two years ago, I wrote about distance running, and how I'd mention it in class to encourage students to work harder. It failed -- because bringing up past events or comparing the students unfavorably to myself aren't effective ways of getting them to make better choices. If I wish to convince my students in the future to think like distance runners, I should do so more subtly.

McFarland USA

Christmas specials started airing on CBS last night with the classic Frosty the Snowman. I wrote before that no school would actually hold classes on Christmas Eve (as shown in the episode) -- that would be even worse than Floyd Thursby Day. In New York, school regularly lasts until December 23rd, unless this is the weekend (as it is on Sunday this year). Thus this year, no school will be open later than Friday, December 21st.

One of my favorite Christmas specials airs on CBS tonight -- Robbie the Reindeer. As it turns out, Robbie is Rudolph's son, but unlike his father, Robbie gets to participate in the Reindeer Games. This is a competition similar to, say, a Cross Country race. (Indeed the steeplechase, in which Robbie competes, is actually a distance event in track -- the 3000 steeple.) Yes, that's why I like it -- because it reminds me of my own days of distance running. I'm glad that the Robbie special is airing today -- on State Meet Saturday.

The one beef I have with it is an inconsistency with the original Rudolph (which will air this upcoming Tuesday). In the original, Donner is Rudolph's father, but in tonight's special, Donner is Rudolph's daughter-in-law. Thus not only has Donner switched generations but genders as well.

Three years ago, there was actually a Cross Country movie -- McFarland USA. When the movie first came out, I briefly mentioned it on the blog. But every year on State Meet Saturday, I watch this movie again. So I turn it on right after the Robbie special.

Here is a description of the movie as written on the back of the DVD case:

In the tradition of Disney sports movies comes McFarland, USA, based on the inspiring true story of underdogs triumphing over tremendous obstacles. This heartwarming drama follows novice runners who strive to build a cross-country team under Coach Jim White (Kevin Costner) in their predominantly Latino high school. Everyone has a lot to learn about each other, but when Coach realizes the boys' exceptional running ability, things change. Beyond their talent, it's the power of family, commitment to each other and work ethic than transforms them into champions -- helping them achieve their own American dream.

Indeed, McFarland USA takes place on the first State Meet Saturday, back in 1987. (And no, it wasn't called Small Business Saturday back then.)

One thing I notice about the movie is that at no point is the distance of the race ever mentioned. It's possible to deduce the distance from a few clues in the movie -- first Coach White drives alongside his athletes and notices that they're running at 12mph, or 5:00/mile -- and then later on, they cross the finish line at around 15 or 16 minutes. But the words "three miles" or "5K" are never explicitly mentioned in the film.

What makes this amazing is that a detailed description of the scoring system is given. Just as Coach White explains in the movie, first place counts as 1 point, second place as 2 points, third place as 3 points, and so on. The point totals for the top five runners are added up to give a team score -- and of course, the lowest score wins.

Indeed, this is what makes the final scene so dramatic. For most of the season, Danny Diaz is McFarland's slowest runner -- he's only on the team to join his two older brothers. Yet due to an injury, the school's fifth runner finishes well off his usual pace. But much to the coach's surprise, Diaz comes in as the fifth and final scorer -- and his points are low enough for McFarland to win. Thus the movie successfully explains why his finishing as McFarland's fifth runner is so significant -- yet the film never specifies the exact distance of the race!

(Hmm, I wonder whether leaving out the distance is intentional. Perhaps the filmmakers wanted to inspire young high school students to try out for XC, but mentioning the distance might scare the potential runners away. Instead, focus on the fun and camaraderie displayed by the McFarland team.)

In the movie, the State Meet takes place in December -- and it appears to be in LA (since I thought I recognized Griffith Park in the background). In reality, the State Meet has never been held on any date other than the last Saturday in November, and it has never been held at any location other than Woodward Park in Fresno. What really makes the timing off is that the date the section finals, or "state qualifier," is given as November 26th. In 1987, this was a Thursday -- in other words, this was Thanksgiving Day. It's unlikely that a XC race would ever be held on the holiday itself. (That the coach rewards his runners by taking them to the beach on Thanksgiving is not an error -- this is California, after all.)

Here is a link to the actual results of the 1987 State Meet as depicted in the movie:

https://www.athletic.net/CrossCountry/meet/90000/results/355173

As you can see, the details of the race are correct in the movie. Danny Diaz really was McFarland's fifth finisher, with a time of 18:04. The distance of the race is 5K (5000 meters), which is a little more than three miles -- therefore my best time wouldn't have beaten Danny's. If I'd been in this race, my best time would have been closer to McFarland's sixth finisher (18:31).

A major theme in this movie is race -- as in ethnicity. (Yes, this is near the bottom of a vacation post, which is when I often write about race.) "White" is the name of the coach, but it's also his race. The runners, meanwhile, are all Hispanic. Thus when the runners call their coach "White" (or Blanco), the name has a double significance.

The first race that appears in the movie is an invitational. McFarland finishes in last place because they weren't used to running hills. (What did I say about hilly XC courses earlier?) So instead, White has them practice running on some mysterious white mounds in their hometown. The mounds turn out to be freshly picked almonds -- which offends the runners, many of whom spend hours every day doing the back-breaking work of picking them! (This explains why a recent DST/time zone proposal referred to the Central Valley as the "Almond Time Zone.") My own coach freshman year had to come up with some creative "hills" (either the bleachers at our school or the side of the flood control channels/riverbeds that I described earlier). My new school was closer to some real hills. (On that hill there was a hose that we sometimes drank water from, just like the runners in the movie.)

The next day, Coach White forgets his daughter's fifteenth birthday. Later on, he makes up for it with a traditional Mexican quinceanera. The family begins to embrace their new community.

Eventually, McFarland wins its first race -- a dual meet against Clovis, 27-28. Notice that the sum of the first ten natural numbers is 55, and so a score of 27 (or less) guarantees a victory. My own coach freshman year gave us the rule of thumb 1-2-5-9-10. These add up to 27, so if our school had the first, second, fifth, ninth, and tenth place finishers, we'd win the meet.

Oh, and Coach White has his runners prepare for the SAT. Yes, what was I saying about XC and academics earlier? At the end of the movie, it's revealed that all seven runners attend college. In fact, no one else in their respective families had yet to finish high school, much less college.

McFarland's XC Team -- and My Team -- Now

At the end of the movie, it's revealed that McFarland won nine state titles from 1987-2001. But it hasn't won any since. What happened?

Well, in 1987, McFarland won the Division III race. All the schools in the state were divided into three (now five) divisions based on enrollment. Since McFarland was a small school, it was always placed into one of the smaller divisions (from III to V).

But nowadays, divisions aren't based on enrollment but on performance. Due to its recent success, McFarland has been pushed up to Division I, where it must compete against Southern Section schools that are several times its size. Last year, the only the girls team advanced to state (where they were buried) -- the boys didn't make it at all. This year, McFarland had only a lone individual girl at state -- her teammates didn't advance. The winning Division I teams in boys and girls are both from Great Oak in Temecula. (Great Oak has over 3000 students, while McFarland has a mere 700.)

As for my own team, I still keep up from time to time on its website. As I wrote earlier, we now have league races on Wednesdays, not Thursdays. The dual meet has fallen out of favor -- instead, our league now has two cluster meets (where all teams in the league compete) and League Finals.

The highlight of our season is still Woodbridge, where many of our runners still set PR's. But the event is no longer held at that high school -- instead it's at a nearby park. And while my Woodbridge races were always in the morning, now the races there are in the late afternoon or early evening (when it's supposed to be cooler). From time to time, my school advances to the State Meet.

One of the senior captains (from my sophomore year) eventually became a math teacher at our school, and he coached the girls XC team as well. Recently he stepped down from coaching, but still teaches math. I wonder whether he ever mentions the endurance of XC runners to inspire his students to work hard at math -- which is what I once desired, and still desire, to say as a math teacher myself.

Conclusion

Ah yes -- Thanksgiving break is almost over, and it's time to start thinking about math (and other classes) again. Maybe someday I really will inspire my math students to think like distance runners -- but that's neither here nor there.

Both of my districts will reopen on Monday, and so that's when my next post will be. I hope you enjoyed your Thanksgiving.

Tuesday, November 20, 2018

Floyd Thursby Day Post

Table of Contents

1. Pappas Question of the Day
2. Who Is Floyd Thursby?
3. What Is Floyd Thursby Day?
4. Is Floyd Thursby a Traditionalist?
5. Floyd Thursby and the School Calendar
6. Back to Our Regular Traditionalists
7. A New Commenter: Rob Craigen
8. Conclusion

Pappas Question of the Day

This is my first holiday post of Thanksgiving break. As often happens during vacation periods, the most interesting Pappas question of the week occurs on a day I don't post. Today I will actually discuss yesterday's Pappas question:

Find x to the nearest whole #.

[Here is the given info: in Triangle ABCBC = 22, AC = 7, AB = x, Angle A = 100, Angle B = 20.]

This isn't strictly a Geometry problem, since it requires using trigonometry on an oblique triangle (although a few Geometry texts actually do mention the Laws of Sines and Cosines.) To make it easier, let me restate the givens as follows:

a = 22, b = 7, c = x, A = 100, B = 20.

This uses the traditional notation where a lowercase letter represents the side opposite the angle with the same capital letter. Anyway, let's try using the Law of Sines to find x. This requires finding the third angle C = 60, since this is the angle opposite the goal side x:

b/sin B = c/sin C
7/sin 20 = x/sin 60
x = 7 sin 60/sin 20
x = 17.72

So the desired side is x = 17.72. The only problem is that this was yesterday's problem -- and that date was the nineteenth. We can justify rounding 17.72 up to 18, but not all the way up to 19.

Is there an error here? Let's try using the Law of Sines again, but with a and A rather than b and B:

a/sin A = c/sin C
22/sin 100 = x/sin 60
x = 22 sin 60/sin 100
x = 19.35

Hmm -- this answer correctly rounds down to 19 now. In other words, we obtained two different answers depending on how we solve the problem. So what gives?

Here's the thing -- most of the time, when we're asked to solve a triangle, we're only given three parts of the triangle. We use the Law of Sines if we're given AAS or ASA (or SSA, the ambiguous case) and the Law of Cosines if we're given SAS or SSS.

But in this problem, we're given four parts of the triangle, which is too many. Whenever we're given too much information (an overdetermined problem), chances are great that some of the givens will actually contradict each other. Here are two (admittedly silly) examples:

a = 5, b = 5, c = 5, C = 70
a = 4, b = 5, c = 6, C = 90

The first is an equilateral triangle that isn't equiangular, while the second is a right triangle whose sides violate the Pythagorean Theorem. Another less obvious example is:

a = 4, b = 6, A = 30, B = 60

This is a 30-60-90 triangle, yet the longer leg isn't sqrt(3) times the shorter leg. An example of an overdetermined problem in Algebra I is if we were given three variables in two equations. Most likely, the solution for the first two equations won't fit the third. (Maybe if we're lucky, the three lines will be concurrent, but this is rare.)

Technically speaking, last Thursday's Pappas problem was also overdetermined, but fortunately, the givens didn't contradict each other. In general, if there are two different ways to solve a problem, with each method using some of the givens, then the problem is overdetermined.

There is actually a third way to solve yesterday's Pappas problem -- the Law of Cosines:

a^2 = b^2 + c^2 - 2bc cos A
x^2 = 7^2 + 22^2 - 2(7)(22)cos 60

Notice that we can almost solve this without a calculator, since we know that cos 60 = 1/2:

x^2 = 7^2 + 22^2 - (7)(22)
x^2 = 49 + 484 - 154
x^2 = 379

Without a calculator, we at least know that x is between 19 and 20. A calculator gives the solution to two decimal places as x = 19.47. This does still round down to 19, but just barely. Still, 19.35 and 19.47 are really two different answers, and along with 17.72 we have three different solutions to the same problem.

Also, we technically used all four givens to use the Law of Cosines, but only because we needed both 20 and 100 degrees to find the 60 degrees that we actually take the cosine of. I suspect that this is how Pappas originally intended us to solve the problem, with the Law of Cosines -- but she decided to get cute and have us calculate the angle via Triangle Sum. She didn't realize that by doing so, she opened the door to using the Law of Sines to find a solution -- and by doing so, we found two solutions different from the intended solution (with one of them dramatically different). When I first saw this problem, I immediately used the Law of Sines and didn't think to use Cosines at all (until I got an answer using Sines that didn't match the date).

As the problem is written, there is actually no solution because the givens are contradictory -- since there are too many givens. Next time, Pappas should just give the angle opposite x as 60 and leave both 20 and 100 out.

Who Is Floyd Thursby?

Today's special holiday post is titled "Floyd Thursby Day Post." But who exactly is Floyd Thursby?

Well, Floyd Thursby is a traditionalist. He used to comment regularly at the Edsource website -- and he still does from time to time. His most recent comment was from July:

https://edsource.org/2018/pressure-builds-to-change-how-california-measures-student-progress-on-state-tests/600062

Floyd Thursby:
I have an idea, why don’t we skip the tests and just ask kids to draw a smiley face and tell us if they are happy. We will not rate either, for who are we to judge smiley faces and what really is happiness? Let’s all just feel good and know that people are good and try their best. No borders, no profits, no prisons. Everyone is good. Except Trump. He’s bad.

(In case you can't tell, Thursby is being sarcastic here.)

Thursby used to post regularly around the time I first started my blog, and from time to time I quoted him as much as I did the other traditionalists.

Since Edsource is a Californian website, I assume that Thursby lives here in the Golden State. In fact, he appears to be from the Bay Area.

By the way, I suspect that "Floyd Thursby" is a pseudonym. It refers to a name of a character in the novel The Maltese Falcon. (I've neither read the novel or watched the film. Indeed, all I know about it is via a parody, "The Case of the Maltese Pigeon," that appears on Square One TV/Mathnet.)

What Is Floyd Thursby Day?

Floyd Thursby Day is the Tuesday before Thanksgiving -- in other words, it's today. An equivalent definition is the Tuesday in the 20's of November (or the first such Tuesday if there's more than one.)

I call today Floyd Thursby Day because that particular traditionalist used to mention that day quite often in his comments. Here is a common reference:

https://edsource.org/2014/vergara-rulings-strong-words-in-the-end-will-make-little-difference/63113

Floyd Thursby:
Let principals decide. Then when a principal calls a teacher into a meeting and says were you really sick the Tuesday before Thanksgiving? What do you think of this parent’s complaint? I observed you and you don’t seem to be focused? Why are your students not improving as much as Ms. so and so’s students on the test? Why are you not doing school loop on time and other teachers are? When this happens, they’ll take it seriously. They’ll improve. They’ll be nervous. They know that a wrong response may cost them their job. It’s like any other job. Principals will have power, and that will cause better work. Now teachers can ignore it.

In Thursby's district, Tuesday is the last day of school before Thanksgiving. As we know, in some district students must attend school tomorrow, while in others (such as the district whose calendar the blog observes), Friday was the last day.

Thursby clearly believes that there are many problems with education, but unlike other traditionalists, his biggest concern isn't standard algorithms, eighth grade Algebra I, or AP Calculus. He believes that many problems with education lie with us -- the teachers. And one of our problems has to do with teacher attendance.

One problem with Thanksgiving is that people wish to spend time with their families, but these day, our families live across the country. The holiday marks one of the biggest travel days of the year, and airline tickets are hard to come by, since demand is high while supply is low. Originally schools were always open until Wednesday, in the decades before airline travel was common. Since so many students, parents, and teachers wanted to travel on Wednesday, schools (including Thursby's) began to close that day, so that Thanksgiving became a five-day weekend. But in many cases this isn't enough, since many had to leave on Tuesday to beat the Wednesday rush. In my districts we avoid this by closing the whole week, but in Thursby's the teachers just take Tuesday off too.

In this same thread, he writes:

Floyd Thursby:
I think you could legitimately expect most teachers not to miss any days most years because they have so many days naturally off, they can use those for personal chores and most of us need a day off or Saturday for that.

To me, part of the problem is that demand for airline travel and other excursions is highly dependent on school schedules. When schools are closed, students and parents are able to travel. Therefore, the cheapest days are when schools are open. The same is true for Disneyland and other amusement parks -- ticket prices are highest when schools are closed and lowest when schools are open. This isn't a problem for most people, but it is for those who work at the schools -- the teachers.

I'm sure Thursby would make the valid argument that loss of flexibility is a fair price for teachers to pay for having so many days off in the first place. Office workers might get only two weeks off, but they can choose the weeks when airline and amusement park prices are low. Teachers get more than two weeks off, but they are stuck with the weeks when airline and amusement park prices are high.

As a teacher myself -- well, a sub, but I did teach for one year -- I must defend us here. Not all of us are looking to take extra days off. Two years ago, I linked to other teacher blogs as part of Tina Cardone's "Day in the Life" project. That year, I even mentioned Floyd Thursby Day since some teachers worked at schools where the last day of school was Tuesday. One such teacher ended up having a snow day on Monday, and so Tuesday was the only day of school that week! Yet she came in and worked hard, as tempting as it might have been to take the day off. So not all of us are as lazy as Thursby makes us out to be.

Thursby also mentions merit pay in this thread. He wants attendance to be considered in determining which teachers deserve bonuses:

Floyd Thursby:
Yes, we’ll have to pay teachers more. Taking away the benefit of a lifetime job will require higher pay and attract better people. Some of the costs will pay for themselves. Until now, the union has opposed merit bonuses and attendance bonuses, said state law disallows them, they divide teachers, or educators. Imagine if instead of an across the board increases, you give an opportunity to gain extra money. Say you tackle the problem of higher absenteeism with a $2,000 bonus for perfect attendence and $1,000 for 3 or fewer, in a district with an average of 11. Every bonus gives the teacher a chance to earn more and afford expenses, but pays for itself as it cuts sub costs. Until now such creativity was unthinkable. Teachers will have to work harder, but they will end up earning more, afford expensive Cities, so it will be good for teachers overall as working harder and having to fear a boss are good for your character and make you self-improve into a better person. It’s good for the soul.

Is Floyd Thursby a Traditionalist?

So far in this post, I've called Thursby a traditionalist. Perhaps this is not the best word to use, since while Thursby wants students to learn more math, he doesn't share all of the same concerns as our main traditionalists Barry Garelick and SteveH.

Thursby strongly believes in merit pay -- and while he mentions attendance as one factor in earning the bonus, the main determinant should of course be test scores:

https://edsource.org/2018/san-francisco-school-finds-key-to-raising-math-scores-teacher-training/599874

Floyd Thursby:
This is a perfect example of how Union Control (Thank God for the long overdue Janus decision) creates nonmarket solutions to market problems. We should pay math teachers more than others if they majored in math and had a high GPA, and we should give a bonus based on test score improvement, which is most measurable in math and English. This seniority/LIFO/tenure situation doesn’t reward or create best results.

Thursby tells us that it doesn't matter whether it's the current Common Core tests (such as SBAC) or the previous CST's (based on eighth grade Algebra I), as long as some test scores are used to calculate merit pay.

He tells us that improvement is "most measurable" in math and English. Not everyone agrees that test scores are a valid measurement of achievement in those subjects.

My main problem is that many students, especially older students, don't necessarily make a full effort at succeeding on the tests. They might be very smart, yet they score low on the tests because they have no incentive to succeed. Therefore, I only insist that if test scores are to be a certain percentage of the teacher's evaluation, then they must be an equal percentage of the students' grades. In other words, 10% of teacher evaluations = 10% of student grades, 50% of teacher evaluations = 50% of student grades, and so on. (It's clearly not 100% since Thursby has already declared attendance to be part of teacher evaluations.)

In fact, we notice that in this article, the school that Thursby commends for raising test scores uses lessons that are decidedly not traditionalist:

On a recent morning, 4th-grade teacher Sara Liebert led a multiplication lesson with almost no lecturing or standing in front of the class. Instead, she wrote “120” on the whiteboard and asked students how many ways they could multiply numbers to reach that product.
While they debated among themselves and penciled equations on scratch paper, Liebert roamed from table to table, checking their progress and writing correct answers on the board.
Then she had them do the same exercise with “360” and “720,” so they could see the links between the numbers. At the end of the 45-minute lesson, most of the students could easily decipher the jumble of 3s, 5s and 12s that combine to make 720.
“Five years ago the way I taught was, ‘Let me show you, let me show you,’” said Liebert, who’s been teaching for 12 years, the past seven at John Muir Elementary. “Now I’m more of a guide while they do the math themselves. You can see how much more independent they are, how much more engaged. They’re thinking like mathematicians.”
Notice that this teacher's scores rose dramatically. Another traditionalist might argue that of course they improved, since she's teaching Common Core methods for the Common Core test -- are these fourth graders bound for eighth grade Algebra I or senior-year AP Calculus? But to Thursby, all he cares is that some sort of test scores are going up.

Floyd Thursby and the School Calendar

As I watch the news tonight, one of the lead stories is the holiday traffic. The anchors stress that travelers should have left hours ago if they wanted to beat that traffic -- which is at odds with having perfect attendance at a school that's in session today. And if you teach at a school that isn't out until 3:00 on Wednesday and not a second earlier, or work at an office that's open until 5:00 Wednesday and not a second earlier, it's impossible to have both perfect attendance and a smooth ride.

Many students believe that they're entitled to several non-academic free days -- and they'll call anyone "mean" if they try to make them do work those days. This includes not just the last day before Thanksgiving, but the last day before other holidays or the last day of school. And it also includes the first day of school and first day after holidays.

Some students might even extend this to Fridays -- they believe that all Fridays should be easy days (and all Mondays). But if we were to cancel school on Fridays, then students would believe that they're entitled to free days on Thursdays, and so on. In other words, the purpose of having school on Fridays is to keep them working hard on Thursdays. Parents must put pressure on their students to keep them working hard before the holiday.

But some parents encourage their students to slack off by pulling them out of class early to beat the holiday rush. So teachers must put pressure on parents to keep their kids in class before the holiday.

And then some teachers encourage slacking off by leaving school early to beat the holiday rush. Now it's Thursby's turn to put pressure on teachers to stay in school before the holiday.

At Thursby's school, teachers want to take Tuesday off to beat the Thanksgiving traffic. But if the district were to close on Tuesday (and Monday), then more people would travel those days. So then teachers would take Friday off to beat the traffic -- and who knows how many other days. But with a short two-day week, teachers, parents, and students are likely to take only one or two days off.

In order to beat traffic, one must take off days that are still officially work days. It's impossible to beat traffic and still have perfect attendance.

By the way, this reminds of the Labor Day debate. It definitely makes a clean transition from summer to start school after Labor Day. But many students think that they're entitled to free days of no work at the start of the year. By starting a week or two before Labor Day, students slack off until the "real school year" starts after Labor Day -- it marks a natural transition point. But if the first day of school isn't until after Labor Day, they slack off until some random date in September. The same is true at the end of the year and Memorial Day -- except, of course, that the existence of finals week forces the students to work hard until the actual end of the year.

Around the first year of this blog, I tutored for students who attended a local Catholic school. Back then, the first day of school, last day of school, last day before/first day after Christmas, and last day before/first day after Easter were all Wednesdays. (Nowadays, only the last day before Easter and the last day of school are Wednesdays.) These set up short three-day weeks before and after vacations for everyone to slack off, so that they'll work hard during the following/preceding five-day weeks.

And in some ways, these even applies to time. I once subbed at a school that dismissed at 3:02. A common problem at many schools is for students to start packing up before the bell rings. At this school, the students often start packing at 3:00, as if that's when "the real school day" ends. But if the bell were to ring at 3:00 instead, they'd start packing at 2:50-something, which might be much more than two minutes before the bell.

I'm not sure whether I fully agree with this sort of school calendar, but it's something to think about in light of Thursby's comments. Students, parents, and teachers all believe that they're entitled to extra "chill time" at the beginning and end of periods, weeks, terms, and school years. So we might set up the school day and calendar that encourage us all to limit that "chill time" to a fixed length.

Back to Our Regular Traditionalists

Since today is Floyd Thursby Day, I devote this post to Floyd Thursby. But this isn't to say that our regular traditionalists have been quiet lately. Over the weekend, Barry Garelick posted on his blog:

https://traditionalmath.wordpress.com/2018/11/18/beliefs-about-understanding-in-math-dept/

Here are some of many beliefs about “understanding” in math.  It was hard to choose from so many candidates, but feel free to add some of your own.  
We shouldn’t be teaching kids algorithms before they have the conceptual understanding.
Of course, Garelick criticizes this belief. But let's look at what he quotes from another "blogger":

Next year’s teachers that are used to students using an algorithm for multiplication are aghast when students use unsophisticated strategies like counting by ones by drawing pictures or partial product by drawing boxes, or when the students seem to not have any idea what to do. “What do you mean, just multiply!” But to “just multiply” by mimicking an algorithm isn’t part of what students had been doing. These teachers shrug in frustration and teach “the only right way”. Students are left feeling either shafted by the previous teacher or, most likely, that they must just not be “good at math”. 

Here Garelick ignores the many students who are taught the standard algorithm for multiplication, struggle to learn it, and then conclude that they aren't "good at math." He appears to assume that the only students who feel they aren't "good at math" are those who are taught nonstandard methods.

By the way, the other two beliefs about "understanding" highlighted in this post are:

“Students who fail to understand a concept are unable to know how to use it or build upon it. They will end up with misconceptions that can go undetected for months or years.”

“In the past, math classes were about teaching facts, skills and procedures with no understanding,and mechanized drills.”

Let's see what frequent commenter SteveH has to say about this post:

SteveH:
Your goal is like shooting fish in a barrel, but will a teacher audience suddenly realize that what they were (ironically) directly taught by rote is fundamentally wrong? Then there are the educators who know exactly what they are doing – defining the learning process to match how they want a classroom to operate. It’s all about them – “the process is the product.” Beyond the very low level of the Common Core, they abdicate all responsibility for skill enforcement, and in the case of eliminating algebra in 8th grade, they ensure that many kids will never live up to their potentials.

At this point SteveH then launches his usual tirade about "Pre-AP" math (which I partly agree with, but not necessarily his solution), which I don't need to repeat. So let's skip to his second comment:

SteveH:
How do they test for this? We have seen many of their silly examples, like the perimeter question. Traditional math is always taught by “connecting those ideas to what they already know.” There is a lot of understanding that comes from mastery of sequentially scaffolded units in a traditional textbook. That scaffolding and building of skills requires a lot of understanding at many levels. This develops proper understanding a level at a time from the bottom up. There is no magic top down understanding that makes doing P-sets simple for each individual. In-class group projects hide individual fuzziness and allows them to ride the coattails of those who most likely are getting help at home or with tutors. We NEVER hear how these educators support individual success on homework. They only care about what goes on in class. They talk about conceptual understanding, but don’t have a clue how to create it for STEM students.

Of course, I can't help but think about last week of subbing, where I met the two girls who already knew how to solve systems by elimination. One of them indeed was tutored by Kumon, while the other was independently studying for SSAT. SteveH would insist that without all that extra tutoring, neither girl might have even been enrolled in eighth grade Algebra I.

SteveH writes about "P-sets" (problem sets) and admits that they aren't simple. But many students, if they don't find them simple, will refuse even to attempt Question #1. I often like how students who don't want to do P-sets are more willing to participate in projects. But here SteveH implies that the weaker students are just "riding the coattails" of the students who would have succeed on the P-sets in the first place, so activities don't result in any additional students learning.

Again, I beg to differ. The fourth grade activitiy given by Sara Liebert above encouraged students who wouldn't have been engaged by a traditional P-set. And another Sara(h) wrote the same in her most recent post -- of course I mean our favorite Sarah, namely Mrs. Carter:

https://mathequalslove.blogspot.com/2018/11/twelve-basic-functions-challenge-in-pre.html

A few weeks ago, I had my best lesson of the year so far in pre-calculus. My students were engaged like never before, and they became super competitive throughout the activity. They did way more questions than I ever would have been able to get them to do if I had just given them a homework assignment. When they came into class the next day, they begged to do an activity similar to the previous day's activity because it had been so much fun. Yes, students begging to do math. It made my heart smile. 

I emphasize that sentence -- "They did way more questions than I ever would have been able to get them to do if I had just given them a homework assignment" or traditional P-set. I can assure you that students wouldn't be "begging to do math" in any class taught by a traditionalist.

A New Commenter: Rob Craigen

There is another commenter here in this thread at the Garelick blog -- Rob Craigen. Strictly speaking he isn't a new commenter as he's posted there before, but this is the first time I quote him here. He wrote an especially lengthy response to Garelick's post.

Rob Craigen:
Referencing the “Student 1 – Part 2” video there are many problems evident in what the teacher does here, so sorry for the long list to follow (and I’ve surely missed some stuff)

By the way, Garelick provides the link to the video, posted by another Rob (Robert Kaplinsky):

https://robertkaplinsky.com/why-depth-of-knowledge-is-critical-to-implement/

Here we discuss the problem: "List the dimensions of a rectangle with a perimeter of 24 units."

Rob Craigen:
1. The ill-posed problem. I’m complaining both about the problem and also about the use of this category leap to try to force a point about formulas not supporting understanding.

Here Craigen uses "ill-posed" to mean "open-ended." It's obvious that this problem has more than one correct answer. Not enough information is given to find a unique solution. It's the exact opposite of yesterday's Pappas problem, where there are too many givens for there to be any solution.

Rob Craigen:
2. “List the”. Huh? There are generally TWO dimensions for a rectangle. “List” a list of two things? This is a misdirection. Not that it’s bad — I’ll ask students for “ALL the solutions in positive numbers x, y to the equation x^2-6x+y^2-8x +25 = 0” and be happy when they provide the single unique solution x=3, y=4. But I don’t ask this of novices who are first trying to grasp what equations in two variables mean and what one means by a “solution” or who lacks the requisite algebra background to crack this one.

And then Craigen continues on about what a "list" is. I point out that in computer science, the number of elements of a list can be 2, 1, or even 0. Speaking of lists, let's skip to #4 on Craigen's list, since #3 is all about the definition of "list" again.

Rob Craigen:
4. I dislike that the teacher “leads” the student throughout, including leading him astray. You can hear the student listening for cues in the teacher’s questions. The teacher’s voice signals approval when the student writes “24 units” along one side: “okay … ” (signalling “correct so far” so the student believes they are on the right track) “…so how long are the other sides?” (Now the student can infer that the teacher believes by putting that number there, the student was indicating that was the length of the labelled side. And the teacher said “okay”. So if he didn’t think so already the student now “knows” that it is correct to understand that this side has length 24).

Many students are turned off by hearing their math teachers tell them that they are "wrong." Indeed, it's fear of being called "wrong" that leads students to leave traditional P-sets blank. The purpose of giving an open-ended (or "ill-posed") question is for there to be more than one correct answer, so that students are less likely to be "wrong."

But unfortunately, a length of 24 doesn't lead to one of the infinitely many correct answers. (As Craigen writes later on, this would imply that the width is negative.) We seek out a way to inform the student of this without using the word "wrong."

Rob Craigen:
5. Now using good Socratic technique, when the student is now apparently lost, the teacher prompts “so this side is 24 units long?” Student: “Yeah”. The teacher has now effectively reinforced the misconception and signalled the student to use that as a starting point for finishing the problem.

6. The teacher asks how long is the opposite side — the student correctly replies (using obviously formulaic knowledge about the properties of rectangles — what ought to be recognized as “understanding”) “24” But this display of understanding goes unremarked.

Notice Craigen's use of the words "astray" and "misconception." To him, the only intellectually honest thing for the teacher to say after the student writes 24 is "You're wrong."

The problem is that human beings aren't Vulcans -- we're emotional, not logical. If we tell people that they're wrong, they're more likely to quit or defend themselves rather than correct themselves. In order to convince others to change, we should do so without using the five-letter w-word. I admit that this is difficult in math where answers really are incorrect, but again, human beings don't suddenly become logical just because they're in a math class.

I think back to the class I subbed in last week. I'd called one guy to the front of the room and asked him to solve a system of equations by elimination. But then he just added the two equations when he needed to multiply one of them by a constant first. So I said to him, "The name of this method of solving systems is elimination. Which variable did you eliminate?" He then quickly realized that he needed to multiply first. I suspect that if I had told him "You're wrong," he would have either quit and sat right back down or defended his error.

Is there a way we could have corrected the student who gave the length as 24 -- without either leading him astray or using the five-letter w-word? Perhaps we could have labeled the opposite side as 24 quickly and asked him to add 24 + 24, so that he'd have realized faster that he's wrong.

Garelick responds to Craigen's comment:

Barry Garelick:
“…a rich problem is almost always a classical word problem with some information taken away. In other words it is an ill-posed problem, such as “The difference of two numbers is seven. What are the numbers?” ”

In the meantime, the poor 6 and 7 year olds presented with this so-called “rich problem” feel they are bad at math, which is the opposite of what the purveyors of “rich problems” wanted.

OK then, suppose we have two group of six- and seven-year-olds. To one group we teach them Common Core methods and give them the rich problem mentioned above. To the other group we teach them the standard algorithm for subtraction and ask them to find 20 - 13. Which task is more likely to lead to the students feeling they are bad at math? Garelick would probably say the first task, forgetting that some students will begin by subtracting the units place as 0 - 3 = 3, and then the (traditionalist) teacher would immediately say "You're wrong!" You can't tell me that this won't cause the student to think they're bad at math!

Conclusion

I like to sneak the more controversial comments (especially those relating to politics or race) into the bottom of holiday posts, and this one is no exception.

It's still Floyd Thursby Day, so let's check out the following link:

https://sfpsmom.com/tracking-what-happens-when-your-are-in-the-dumb-class/

This post is about tracking -- and we all know what that means. Floyd Thursby comments:

Floyd Thursby:
You are assuming effort is not at play. Cuban Americans (Latino) and Nigerian Americans (black/AA) outperform whites. In California, Asian students study 13.8 hours a week from 11-18 and whites 5.6, and 60% of Asian American kids are taught to read before starting Kindergarten vs. only 16% of whites In San Francisco the white percentages are higher as many are Russian and immigrants, or Jewish American, or in general highly educated. The average California kid watches over 40 hours a week of TV but those making it to a UC about 10, on average.

The response by the blog author, Alison Collins, speaks for itself:

Alison Collins:
Wow! So let’s see, to restate: “Asians are better parents”, “black parents let their kids watch too much TV” and “whites are lazy”…. Thanks for proving my point that racial bias underpins this whole debate.

Let's end this post right here. My next holiday post will be on Saturday.