Whenever I go to the WordPress Stats page for this blog, I see that my most popular post (most popular by far) is “Names of Polygons,” which I posted on December 10, 2010! It had 361 views last month, nearly… Read More ›

# Math

## Ancient Babylonian trigonometry? Really? Really???

It’s pretty clear what this clay tablet says, right? Obviously it’s written in… Oh, wait, maybe it isn’t so obvious. You probably don’t read Babylonian, or Akkadian, or Sumerian, or whatever language these cuneiform carvings represent. But this tablet has… Read More ›

## Do negative numbers exist? And why do two negatives make a positive?

A brief interchange on Facebook yesterday and today with three of my former students prompted this discussion of the two questions stated in the title of this post. It all started with this implausible claim from a reliable math website:… Read More ›

## “If it ain’t broke, don’t fix it?” (Rethinking quadrilaterals)

Why on earth would we spend two whole days rewriting our Honors Geometry quadrilaterals unit? Our textbook, after all, contains a perfectly serviceable sequence of four lessons on this topic: These lessons are adequate. In the words of the standard… Read More ›

## Coding in middle school math

Google Blockly? What’s that? And should we say coding or computer programming? We’ll deal with that terminological question in the last paragraph, but let me first tell you about Blockly and about the workshop we had yesterday. A group of… Read More ›

## Yes, the Mission Hill presentation was successful.

Yes, the Mission Hill trip was successful. Two weeks ago, I promised to tell you the results of our decision to replace Chinatown with Mission Hill as one of the eight Boston neighborhoods we visit each summer as part of… Read More ›

## 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 ›