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Conjectures and Counterexamples 1
Some natural conjectures about 1-2 Nim The person who goes first wins. The person who goes second wins. Who wins depends on how many counters there are. It doesn’t matter what you do until there are 5 counters left. You win if there [...]
3 Steps to Change Math Class
Over the years, we’ve thought a lot about the steps one needs to take to go from beginner to expert at teaching math. It wasn’t enough to explain or demonstrate something extraordinary. Teachers needed to get excited about [...]
Perils and Promise of EdTech (featuring Prime Climb)
We are, as a rule, skeptical of the promises of the EdTech world. When so many students (young students especially) need hands-on materials, why put them on screens? And why do so [...]
Conjectures are more Powerful than Facts in the Classroom
There’s a place for facts in math class. They end experiences. Think of a fact as a snapshot you take from the top of the mountain you just climbed. It reminds to of the [...]
Our Remote Curriculum
We recently took on a massive overhaul of our summer/intervention curriculum. Seattle Public Schools wanted to use it for some number of students; this being the pandemic and [...]
A matter of justice
There should be no doubt that racist ideas are bankrupt, and racist policy is unjust, that injustice toward any of us hurts all of us.
Understanding one-digit multiplication video
This video follows up on the previous blog post, on understanding multiplication. Put in the time now and get this foundational understanding laid right.
Understanding Multiplication Part 1
What does “solve 3 x 8” mean? There are actually two crucial pieces of information to parse for this to mean anything. “x” means “groups of” First off, the [...]
Understanding subtraction part 2: multi-digit subtraction
I posted a little while ago about the importance of representations in subtraction. Today, I’m sharing a followup video on how to extend that understanding of fractions to [...]
A math game with its own theme song?!
A teacher named Mark Esch emailed me recently to ask about using one of our classroom games, Horseshoes, in a movie he wanted to make. When he sent it to me, I was blown away. It’s fun, and does a great job explaining the game. But [...]
A meditation on commutativity of multiplication
We’re in the final stretch of the Kickstarter campaign now! The last ten days will determine just how successful the campaign is. Keep spreading the word, and hopefully we’ll get to 4x of our campaign target, hit all the [...]
Free printable Tiny Polka Dot starter deck
I recently committed to donate up to 1000 Tiny Polka Dot games if people could help us find good homes for them. Within four hours of a mass email going out, 359 people had filled [...]