## A Math Magic Trick

I’ve been meaning to write this lesson up for a long time. Finally, here it is, in all its glory. You can check it out below, or find it here on the lessons page. This trick is an extraordinary introduction to the power of algebraic thinking, and a reminder of what makes algebra so awe-inspiring. When I was in middle …

## Warm Ups: Number Talks and More

In my last blog post, I wrote about creating Doing-Math and Thinking-Math classrooms. One small but important ingredient I’ve found helpful for both is a good warmup activity. The goal of the warmup activity is to get students thinking and active right away. The barrier to entry should be extremely low, so that everyone can able to participate. It’s a …

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We’ve recently invented a game that surely already exists in some form already. But it’s been super fun to play, and we’ve been using it with kids and teachers at all grades. It’s kind of magic. We don’t have a scoring system for the game, and I don’t think it needs it in many cases, but if you have ideas …

## Bill Clinton Teaches Arithmetic, Plus Exciting News on abc

Last week was a very big week for mathematics. First of all, Bill Clinton made arithmetic the centerpiece of his speech at the DNC. While it may not be new to let arithmetic affect policy, it has been absent from politics for some time. John Stewart hailed its return saying I never thought I’d say this but I have missed …

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## Triangle: A new math card game

A 10-year-old I meet with greeted me yesterday by telling me that he’d had an idea for a game called “Triangle” right before going to bed. He described the basic premise, and we toyed with different ideas for game play. As we worked, I mentioned my three guidelines for inventing a game: It should have a clear goal. It should …

## Free At Last

If you want to see someone really committed to freedom in education, check out Free At Last: The Sudbury Valley School, which you can read online at the link, if you want. I went there for the first chapter, on teaching arithmetic, but stayed for the later chapters. But read that first chapter, with the surprise at the end. Consider …

## Laplace on the profundity of base 10

It is India that gave us the ingenious method of expressing all numbers by means of ten symbols, each symbol receiving a value of position as well as an absolute value; a profound and important idea which appears so simple to us now that we ignore its true merit. But its very simplicity and the great ease which it has …