Math Game: Chopsticks

Math Concepts: counting up to five, thinking ahead.
Players: two or more.
Equipment: none.

How to Play

Each player starts with both hands as fists, palm down, pointer fingers extended to show one point for each hand. On your turn, use one of your fingers to tap one hand:

• If you tap an opponent’s hand, that person must extend as many extra fingers on that hand (in addition to the points already there) as you have showing on the hand that tapped. Your own fingers don’t change.

• If you force your opponent to extend all the fingers and thumb on one hand, that makes a “dead hand” that must be put behind the player’s back, out of the game.

• If you tap your own hand, you can “split” fingers from one hand to the other. For instance, if you have three points on one hand and only one on the other, you may tap hands to rearrange them, putting out two fingers on each hand. Splits do not have to end up even, but each hand must end up with at least one point (and less than five, of course).

• You may even revive a dead hand if you have enough fingers on your other hand to split. A dead hand has lost all its points, so it starts at zero. When you tap it, you can share out the points from your other hand as you wish.

The last player with a live hand wins the game.

Variations

House Rule: Do you want a shorter game? Omit the splits. Or you could allow ordinary splits but not splitting fingers to dead hands.

Nubs: All splits must share the fingers evenly between the hands. If you have an odd number of points, this will leave you with “half fingers,” shown by curling those fingers down.

Zombies: (For advanced players.) If a hand is tapped with more fingers than are needed to put it out of the game, it comes back from the dead with the leftover points. For instance, if you have four fingers out, and your opponent taps you with a two-finger hand, that would fill up your hand with one point left over. Close your fist, and then hold out just the zombie point. In this variation, the only way to kill a hand is to give it exactly five points.

History

Finger-counting games are common in eastern Asia—and they must be contagious, since my daughters caught them from their Korean friends at college. Middle school teacher Nico Rowinsky shared Chopsticks (which is simpler than the version my daughters brought home) in a comment on the “Tiny Math Games” post at Dan Meyer’s blog.