This is the teacher’s “cheat sheet”, named after formula sheets and resources we give our students during tests to help them succeed. 

The purpose of this page is to provide you with resources and quick videos you can watch to reinforce concepts you may need to teach.

These videos are aimed at educators, but could be shown directly to students as well. They come from our Operations module (coming very soon!) and we’re working on a new series of videos. 

We are also working on a series of videos for students associated with our Ask a Mathematician program.



Each section contains a number of videos related to that topic.

Please Note: these videos come from our Operations (Part 1) course so they occasionally make reference to other videos or ‘as we saw earlier’.

We are also working on updating many of these videos so the format / content of them may change over time. 

If you’d like to ‘follow along’ with the videos we are using the free tool PolyPad for most of the online manipulatives shown: https://mathigon.org/polypad

Place Value

Here’s the PolyPad if you want to ‘play along’: https://mathigon.org/polypad/GYEmcUJpefgZ9A

Operations with Whole Numbers

More on Whole Numbers

Operations with Fractions

More on Fractions

Operations with Decimals

More on Decimals

Operations with Negative Numbers

More on Negative Numbers