Hundred Chart Nim
Math concepts: addition and subtraction within 100, logical strategy
Number of players: 2 or 3
Equipment: printed hundred chart (also called a hundred board) and beans, pennies, or other tokens with which to mark numbers — or use this online hundred chart
Place the hundred chart and a small pile of tokens where both players can reach them.
How to Play
Allow the youngest player choice of moving first or second; in future games, allow the loser of the last game to choose. The first player chooses any number from 1 to 15 and places a token on that square of the hundred chart.
On each succeeding turn, the player adds either 5, 10, or 15 to the most recently marked number and places a new token on his sum. Play alternates until no more tokens can be placed.
The player who places the last legal token (on one of the squares from 96-100) wins the game.
1 — Allow players to add any number from 1 to 20 on each turn. The player who reaches 100 wins the game.
2 — Count Down: Start at 100 and subtract 5, 10, or 15 per turn. The player who reaches zero wins the game.
3 — Mental Math: Try the game (or either variation above) without a hundred chart, keeping track of the numbers in your head.
Nim is a traditional folk game of uncertain origin (similar games are played in many places around the world), and it has always been a favorite at our Math Club meetings. This version of Nim gives young children a chance to build fluency with double-digit arithmetic, an important foundation for their future study of mathematics.
This is post #2 in my Hundred Board Series.