This activity is a number version of the word game Boggle. Encourage students to be more creative with their equations by introducing a points scoring system, one point for every number used in an equation. This will push them to strive for complex equations, such as 4 + 5 + 8 = 14 + 3. The game also develops the “family of facts” idea. For example, from this triangle:

the following equations can be written:
4 + 5 = 9
5 + 4 = 9
9 – 4 = 5
9 – 5 = 4
With this arrangement:

many equations are possible, such as:
13 – 3 = 1 + 4 + 5
13 – 5 = 4 + 3 + 1
1 + 3 + 4 + 5 = 13
After a few attempts at playing the game, you could ask students to make up their own board. This is best done by starting with four single numbers in the centre squares and placing larger numbers around them to give the greatest possible number of equations. For example:

Answers to Activity

A game of addition and subtraction