Skip to content
the grown-up commonsPlay togetherBack to room

← Learn

The Arithmetic of the Chessboard

Three short lessons on the numbers in sixty-four squares: coordinates, the old doubling story, and how many squares there really are.

For grown-ups, from what GambitTales teaches children at Spark & Anvil.

  1. Lesson 1Coordinates
  2. Lesson 2The doubling story
  3. Lesson 3How many squares
At the table · Two or more, ages 7 and up

Rice on the board

You'll need: A chessboard (or a drawn 8 × 8 grid), a cup of rice.

  1. Put 1 grain on the first square, 2 on the next, 4, then 8, doubling.
  2. Before going on, everyone guesses which square will first need more than the whole cup.
  3. Keep going until the rice runs out, and count how far you got.
  4. Work out roughly how many cups the last square would need.

Print the guidebook (all lessons + the table activity) →