Mathball

My kids invented a game! If you've been reading this newsletter for a while, you know what a momentous occasion this is. 

We are in the blessed spring here in Alabama, before the heat gets truly unbearable. As a result, we have been trying to stay outside as much as possible. So my older two kids came up with the perfect math game to play in a driveway or on a sidewalk. All you need is some chalk and a ball of some sort.

My son named it Mathball.

How to Play Mathball

To play, you'll want to find a sidewalk, driveway, or other long flat piece of pavement. We use our front walkway. 

Draw a "throwing line" on the sidewalk, and then start drawing arrangements of circles extending away from the line. Fill these circles with numbers. We did a couple of 5s, followed by some 10s, 20s, 50s, and 100s.

Players take turns standing behind the line and throwing the ball. We have used a small kickball and a basketball, and they each work well. 

The goal is to bounce on as many numbers as possible. Every time you bounce on a number, you earn that many points. So you could go for 100, or you could try to bounce on seven different circles throughout the game. Depending on how you've arranged the circles and the numbers, all sorts of different strategies can emerge! 

We like to play three or five rounds, calculating scores after each round. My kids are getting a ton of practice with addition!

Where's the Math?

Obviously, there is a lot of math in Mathball. It's even in the name!

But I want you to notice something in particular about this game - I've left the rules intentionally vague. How many circles should you draw? How big, and how far apart? What numbers should go in them?

All these decisions are ones that you and your kids should make, depending on your math goal and your kids' interest. If you have a kindergartener, you'll probably want a bunch of 1s, 2s, 3s, and 4s. If you have a 3rd grader, perhaps some 25s, 75s, 125s, and 175s are in order. 

But this is a great game to iterate over time. Play a couple of rounds, and then ask your kids "The next time we play this, how should we change the game?" Brainstorm ideas for new variations, but always be sure to ask "How would that change the strategy of the game?"

Let's say you place a single, small circle far from the line and put a massive number inside it. Would that make the game more or less fun? Why? Have you accidentally turned the game into a contest tom hit that one little circle, and is that more fun than the original?

Your children won't be explicitly discussing a bunch of addition problems necessarily, but the mathematical constraints of the game will be a huge part of their analysis. So let them be the game designers! They will have much more ownership over the game if they invent some fun new variation.

All I ask is that, if you come up with a great tweak on the rules, you email me back! I want to share some of the awesome ideas that you and your kids come up with.