Lesson 1.2.3: Domain and Range (Days 16-18)

Since today is August 31st, let's look at the 31st topic on Shelli's list:

31. Observe yourself!  Record your lesson using your phone in your pocket and use it to reflect

Well, I have only an old flip phone that can't record video or audio. The only "phone pockets" action I did earlier this month was to take two inadvertent photos with my phone -- still in my pocket.

Of course, I can still reflect on today's lesson even though I didn't record it. Today's fourth period Math I lesson involves teaching domain and range, in preparation for the quiz on Friday. But there are a few problems with today's lesson.

First, according to the official pacing guide, this week's quiz really only covers today's lesson -- not the lessons for the entire week. So it puts pressure on me to teach it well to make sure that students get it.

The lesson begins with a Desmos activity -- a puppy is placed on a coordinate plane, and students must find its "domain and range" (taking the puppy to be a relation defined by the set of all its points). Then I give them more examples with functions instead of puppies -- students are asked to find the domain or range, or the domain where the function is increasing or decreasing. I end the day with a VNPS review for the DeltaMath quiz on the next day that this class meets, namely Friday.

But it just seems as if I'm squeezing so much in and rushing the lesson. Potential spots for confusion include mixing up domain and range, including on the increasing /decreasing section where students try to name the maximum/minimum y-value, instead of the domain of x-values where the function is increasing or decreasing.

Keep in mind that I have the right to make changes from the official pacing plan -- and indeed, I've already made some changes, but perhaps not the right ones. Sometimes it just seems better if there's at least one meeting day between the lesson and the quiz on that lesson -- so if the quiz is to be on domain and range, that lesson should have been given yesterday, not today. (Then again, I wonder what made the author of the pacing guide to place this lesson on the last class meeting day before the quiz.)

I also wonder whether it's better to have students enter the range as 1 < y < 7 or [1, 7]. I usually lean towards the former for younger Math I kids and the latter for older Math III students, since DeltaMath accepts either form -- and so I do use the former in today's Math I class. But 1 < y < 7 allows an extra opportunity for the students to make a mistake (that is, entering x instead of y for range) that [1, 7] doesn't allow. So I wonder in reflection whether I should have just used [1, 7].

Interestingly enough, first period Math III also gets a domain and range lesson today. Their Desmos lesson is a card sort on matching functions/relations with their domain/range, but their main lesson consists of similar DeltaMath questions. And I do use the notation [1, 7] with the older students.

This is my final Blaugust post. By the way, if you're wondering where my annual "letter to my first year teacher self is," that's now #34 on Shelli's list, not #31. Then again, I sent several "letters" to my first year self earlier this summer on the other blog, "letters" containing songs I could have performed that year (which were in reality songs I'm hoping to sing this upcoming year).

The song for today is Square One TV's "Wanna Be," performed by Bobby McFerrin, a jazz singer:

Refrain:
Wanna be, wanna be,
Anything you wanna be.
Anything you wanna be,
You've got to know math.
Wanna be, wanna be,
Anything you wanna be.
Anything you wanna be,
You've got to know math.

First Verse:
You wanna be a doctor?
You wanna be a nurse?
You wanna fly a jet plane?
You've got to know math first.
You wanna coach football,
Or run a baseball team?
Operate computers,
Be whatever you dream? (To Refrain)

Second Verse:
You wanna be a stuntman,
A scientist?
A photographer,
An archaeologist?
A firefighter, detective,
Fighting fire and crimes?
You'll have to work with a lot of  numbers,
Using math all the time! (To Refrain)

There's a minimum day coming up on Friday to make up for Back to School Night. This is not a "monthly minimum day," and so it won't be a posting day. Instead, my next post is scheduled for after Labor Day weekend, on Tuesday, September 6th.

And with both Blaugust and the Willis unit over, most of my posts will now contain only the song I perform that day (which will now be on the guitar). The Math I lesson I teach that day can be inferred from the title of the post and the song.