By Tom

The other night I was sitting in my living room, on my recliner, preparing lesson plans for the next day. (That’s how I roll, by the way; one day at a time.) As I was working on my math lesson, I looked in my Math Expressions Teachers’ Guide and noticed that the next day was all about finding the area of a triangle. A bell went off in my mind; I remembered something from some Common Core workshop sometime in the last couple of years. So I check the CCSS website and sure enough, area of a triangle is no longer a fourth grade thing. Sixth graders get to do it.

Now, a smarter man would have simply shrugged it off, turned the page to the next lesson and planned accordingly. But I’m not smart. I thought to myself, “I wonder if there’s something in the fourth grade standards that isn’t covered by our textbook. And if there is, maybe I should teach a lesson on that.”

There was. Fourth graders are supposed to “Recognize angle measure as additive; when an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts. They’re supposed to know how to solve addition and subtraction problems to find unknown angles on a diagram in real world and mathematical problems.”

In other words, my students are supposed to know that you can take a ninety degree angle and divide it into a sixty and a thirty degree angle. Or you can take a ninety degree angle and combine it with two 45-degree angles to make a 180-degree angle. Stuff like that.

So I went online to see if there were any resources available. There are. Actually there’s some great stuff from New York State’s “Engage NY” site. So I found myself some resources, came up with a plan for my students, and wrote it up.

Then I checked the time. Continue reading →