Chocolate Chomp
How it works
Chocolate Chomp is a 2-player game. Here's how to play:
You have a chocolate bar consisting of 5 rows and 6 columns of squares of chocolate.
All of the squares are wonderful and delicious except for the bottom left square, which is yucky and will make you sick.
Players take turns removing squares from the bar.
On each turn, a player can take any number of rows from the top of the bar or any number of columns from the right side of the bar.
You lose if you take the yucky square, and you win if your opponent takes the yucky square.
Could you beat an expert at this game if you go 1st? What if the bar is a different size? What if the expert gets to choose the size of the bar, and you choose whether to go 1st or 2nd? When would you want to go 1st and when would you want to go 2nd?
In this activity, students work together to figure out how to beat a facilitator who is an expert at the game. First, they try to beat the facilitator if the bar is 5 x 6 and they go 1st. If they are able to do this, then they try to figure out how to beat the facilitator starting with different sized bars. If there is time, they can also explore variations of the game with different rules for removing squares from the bar.
Why we like this activity
It’s fun! Students enjoy playing the game and figuring out how to beat the facilitator.
It helps students develop algorithmic and game-theoretic reasoning.
It requires students to engage in mathematical habits of mind:
- Using logic and finding and using strategies to beat an expert.
- Looking for patterns and making and testing predictions when trying to figure out when it's better to go 1st or 2nd.
It has a low floor and a high ceiling: Students can start playing the game by trial and error, but figuring out how to beat an expert is more challenging!
This activity was developed in collaboration with the Julia Robinson Mathematics Festival.