Hello, reader! If you intend to post a link to this blog on Twitter, be aware that for utterly mysterious reasons, Twitter thinks this blog is spam, and will prevent you from linking to it. Here's a workaround: change the .com in the address to .ca. I call it the "Maple Leaf Loophole." And thanks for sharing!

## Monday, March 30, 2009

### The Perfect Challenge

I am not a huge fan of making kids memorize things for its own sake. But memorization does have its place. For example, for a student to be able to efficiently simplify a radical, it really, really helps if she recognizes a perfect square when she sees one. For example, $\sqrt{338}$ looks like it would be complicated to simplify, but by the time I'm done with my freshmen, they can do this without a calculator. They notice it's even, so they write it as $\sqrt{169}\sqrt{2}$, and then they recognize that 169 is the square of 13, so they write $13\sqrt{2}$. Done. But recognizing the 169 is the lynchpin.

I actually have them memorize all the perfect squares from 1 to 400. The first 10 they kind of know already, so it's really a matter of learning the square of 11 through the square of 20. How do I accomplish this feat? Bribes. This little exercise is a testment to the lengths a 15 year old will go for a Lemonhead. (Also lemme just say, I'm pretty sure I stole this idea from someone, but I have no idea who or when. I'm not trying to claim credit, just get the word out.)

Once the Perfect Challenge starts, we begin every class period with a short, timed quiz, and they know exactly what will be on it. I just jumble up the questions. If a student can complete it perfectly in the allotted time (60 - 90 seconds, depending on my mood), she gets a piece of candy. We do it every day until every student can do it perfectly. Some years one or two students can do it the first day. It has never taken more than 7 tries.

Here is my Excel Document with 7 quizzes, 2 per page.