Whence significant figures?

Significant digits can arise out of less significant data, right? For instance, you probably learned in ninth-grade science that a number rounded to one significant figure can be magically turned into one with three significant figures simply by changing measurement… Read More ›

For the win!

What a great start for the Weston High School Math Team! In our first Massachusetts Math League meet of the year, our goal was a simple one: to beat Canton. Simple, but definitely not easy, as it almost never happens. And beat Canton… Read More ›

Desmos Redux

We had a productive workshop today, identifying and developing materials for using Desmos — primarily, but not exclusively, in Algebra 2 and Precalc 2.  There are at least two different ways to use Desmos: as a graphing calculator that’s much better than… Read More ›

15th Century crypto

If you’re sufficiently geeky, you will surely want to know something unexpected about the mathematics of functions and their inverses: cryptography in the 15th Century. Why? Because then we’re focusing on the transition from the monoalphabetic ciphers (such as Caesar,… Read More ›

The wrong way to teach math?

A headline writer attached this misleading title to an opinion piece in the New York Times last Sunday. My response (this post) is yet another follow-up to the follow-up I posted on February 18. Apparently the issue just won’t go away! Andrew Hacker continues to… Read More ›


We’re having a dispute about the commonly understood meaning of the word “most.” Don’t look it up in a dictionary; just go by your own intuitive definition. Here’s a sample situation: You’re in a gathering of 12 people, with the following… Read More ›

Why “x”?

If it’s in a TED talk, it’s got to be correct. Right? Actually, not so much. But when the talk is about both math and linguistics, how could I resist? So I just had to watch Terry Moore’s four-minute TED talk… Read More ›

Who needs algebra? — A follow-up

Lucy Brownstein, a high-school student from Brooklyn, wrote a fine response to Andrew Hacker (see my post of February 7). You noticed that I didn’t say something like “a fine response for a high-schooler.” It’s a fine response, period. But still, it’s especially… Read More ›