Euclid’s Game on a Hundred Chart

2008 January 26

Euclid game

Math concepts: subtraction within 100, number patterns, mental math
Number of players: 2 or 3
Equipment: printed hundred chart (also called a hundred board), and highlighter or translucent disks to mark numbers — or use this online hundred chart

Set Up

Place the hundred chart and highlighter where all 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 a number from 1 to 100 and marks that square on the hundred chart.
  • The second player chooses and marks any other number.
  • On each succeeding turn, the player subtracts any two marked numbers to find and mark a difference that has not yet been taken.
  • Play alternates until no more numbers can be marked.

Endgame

The player who marks the last number wins the game.

For Advanced Students

When you play Euclid’s game on paper, circle the original pair of numbers. Collect several finished game boards. Compare the pattern of the numbers marked on each game.

  • Can you explain why some games have few numbers marked and others have many?
  • If you knew the first two numbers, would you be able to predict how many squares would be marked in the end?

For a hint, check out this page at Amby’s Math:

Comments

Cut the Knot

I first discovered Euclid’s game at Alexander Bogomolny’s outstanding website, Cut the Knot. You can play a Java version online here:


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This is post #3 in my Hundred Board Series.


Have more fun on Let’s Play Math! blog:

7 Responses leave one →
  1. 2008 January 27

    Excellent! Don’t know why I didn’t think of this streamlining of the paper-pencil game. thank you.

  2. 2008 January 28

    I’m glad you liked it. Playing with pencil on scratch paper is quick and easy, but using the hundred chart as a game board makes it feel more like a “real” game to me — and the number patterns show up clearly on a chart.

  3. 2008 August 7

    lol lets play math lol
    For me math was allways anything other then playing. Greeting, Niki Buchen

  4. 2008 November 12

    I hate math, or should I say Math hates me. But, I don’t know why I enjoy challenging myself with games that has math on it.

  5. 2009 July 31

    Love it! I am so glad that I came across your website tonight. I am starting my first homeschooling year with my 6 year old this fall and I am really excited about our math lessons. This game will be a great addition to our activities. We are doing a lot with bean bag tossing games for addition and subtraction practice.

Trackbacks & Pingbacks

  1. Magic and Mayhem » Blog Archive » A little math game
  2. Carnival of Mathematics 1000 « JD2718

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