Next week my students and I will be participating in Global Math Week. The goal of the project is for one million students around the world to have a common, joyous, and uplifting experience with math. Over 750,000 students from over 100 countries are already registered. You should too! The topic for this first year is exploding dots, which you can learn more about on James Tanton’s GDay Math website. I want to describe roughly what I plan to do, to help any teachers out there who may be on the fence or unsure how to proceed. I teach upper high school so take that as useful context, but I think the heart of the math works down to upper elementary and could absolutely be adapted for lower grades.
First, I plan to share the video at the bottom of this page to introduce the idea of exploding dots, and have students try to figure out the question at the end of the video.
Watch it if you haven’t seen it already! It’s a great, perplexing introduction to the principles of exploding dots as students work together to figure out what the number is. Depending on how that goes, I may give them a few more or just move on if they get it quickly. Then, we’ll discuss the connections between the two sets of numbers, talk about the “1-2 machine” demonstrated in the video, and expand to a “1-10 machine” — base ten rather than base two.
I’ll have students add a few numbers using the 1-10 machine, and then introduce multiplication. I’ll do a few examples with small numbers, then offer the puzzles of 24617×10 and 24617×11 to see what they can figure out.
Next up is subtraction with dots and antidots, and division. I’m not sure how far we will get but I hope to give students a few division problems to attempt, and to ask them whether they like long division or dividing using dots better. Finally, I hope to introduce the “1-x machine” and do a bit of polynomial division. Not sure if we’ll get to this.
The heart of the lesson is a bit of perplexity and the chance to play with math in a new way. I’ll let different parts of the lesson go longer or shorter as students are engaged with those goals. I would recommend spending time with the examples on the Exploding Dots page and getting to know the content to have some flexibility with what students are engaged with.
I’ll close by saying that I hope students enjoyed the experience, and that this was helpful for them to look at arithmetic from a new perspective.
Global Math Week is not meant to restrict what teachers can do. If you have fifteen minutes, maybe just share the video and connect it to base ten addition. If you have three days, explore polynomial operations and tease students with some of the fascinating unsolved problems that exploding dots reveals. If you’re somewhere in the middle, find some middle ground. If you’re interested in some more technology, check out the web app. Watch the videos on James’s site. Find a way to make this work for you. And happy Global Math Week!