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# Odds and Evens

The numbers on the balls are added together: $4 + 5 = 9$

**If the total is even, you win.**

If the total is odd, you lose.

How can you decide whether the game is fair?

*You might like to experiment with the interactivity below.*

Here are three more sets of balls:

Which set would you choose to play with, to maximise your chances of winning?

Click on the links below to explore each set using the interactivity.

**What proportion of the time would you expect to win each game?**

*You may wish to look at the problem Odds and Evens Made Fair to explore whether it is possible to change the number of balls to make the game fair. *

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Age 11 to 14

Challenge Level

*Odds and Evens printable sheet*

Here is a set of numbered balls used for a game:

To play the game, the balls are mixed up and two balls are randomly picked out together. For example:

The numbers on the balls are added together: $4 + 5 = 9$

If the total is odd, you lose.

How can you decide whether the game is fair?

Here are three more sets of balls:

Which set would you choose to play with, to maximise your chances of winning?

Click on the links below to explore each set using the interactivity.