Thursday, March 10, 2016

Review for Chapter 8 Test (Day 120)

Today is the 120th day of school, according to the blog day count. Therefore today marks the end of the second trimester, but this is relevant mostly for elementary school students (including first graders, since Common Core requires that they learn how to count to 120).

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

As I mentioned earlier, the Chapter 8 Test is on Friday, which means that the review for the Chapter 8 Test must be today.

In earlier posts, I mentioned the problems that occur when a teacher blindly assigns a worksheet that doesn't correspond to what the student just learned in the text. Since I'm posting a review worksheet today, we should ask ourselves whether the students really learned the material that is to be assessed in this worksheet.

For example, most students learn about area at some point in their geometry texts, but only the U of Chicago text includes tessellations in the area chapter. Yet the very first question on this area test is about -- tessellations. So a teacher who assigns this worksheet to the class will then have the students confused on the very first question!

Let's review the purpose of this blog and the reason why I post worksheets here. The purpose of this blog is to inform teachers about the transformations (isometries, similarity transformations) and other ideas that are unique to Common Core method of teaching geometry. The worksheets don't make up a complete course, but instead are intended to be used with a non-Common Core text -- the one that teachers already use in the classroom, in order to supplement the non-Common Core text with Common Core ideas. Another intent is for those teachers who do have Common Core texts, but are unfamiliar with Common Core, to understand what Common Core Geometry is all about. My worksheets are based mainly on the U of Chicago text because both this old text and the Common Core Standards were influenced by NCTM, National Council of Teachers of Mathematics.

So this means that a teacher interested in Common Core Geometry may read this blog, see this worksheet, decide to assign it to the class, and then have all the students complain after seeing the first question because their own text doesn't mention tessellations at all.

I decided to include the tessellation question because it appear in the U of Chicago text. But as of now, it's uncertain that tessellations even appear on the PARCC or SBAC exams. So it would be OK, and preferable, for a teacher to cross out the question or even change it. There's a quadrilateral, a kite, that's already given in the question, so the question could be changed to, say, find the area of the kite, especially if the school's text highlights, instead of tessellations, the formula for the area of a kite.

I admit that it's tricky to accommodate all the various texts on a single worksheet. I included tessellations since this is a drawing assignment that is fun, and I'd try to include them if I were teaching a class of my own. But I also want to include questions that may be similar to those that may appear on the PARCC or SBAC exams.

For example, Questions 2 and 9 are exactly the type of "explain how the..." questions that many people say will appear on those Common Core exams. And so it was an easy decision for me to include those questions.

Another issue that came up is the Pythagorean Theorem. Such questions appear in the SPUR section of Chapter 8 in the U of Chicago, but we didn't cover Lesson 8-7. I dropped the questions that were purely on the Pythagorean Theorem, but I kept two trapezoid questions where the Pythagorean Theorem is needed to find the length of a side or the height. But these questions will confuse a student who has reached the area chapter, but not the Pythagorean Theorem chapter that may be several chapters away.

Then there is a question where students derive the area of a parallelogram from that of a trapezoid. I point out that in other texts -- especially those where trapezoid is defined inclusively -- this isn't how one derives the area of a parallelogram. In the U of Chicago, the chain of area derivations is:

rectangle --> triangle --> trapezoid --> parallelogram

But in other texts, it may be different, such as:

square --> rectangle --> parallelogram --> triangle --> trapezoid

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