Eryn and Ossie were spinning the spinner shown. If the number they got was even then Eryn won; if it was odd, then Ossie won.
This is what we call a fair game as 2 (even) and 1 (odd) come up equally often, so both players have an equal chance of winning.
Suppose they now made the spinner below and played the game again.
(i) Where should the numbers 1, 2 and 3 be put on the spinner so that the game is fair?
(ii) Where should the numbers 1, 2 and 3 be put on the spinner so that the game is not fair?
Solution
(i) As there is only one even number it has to go in the part with the b. 1 and 3 can go in either of the smaller sections.
(ii) If 2 is anywhere other than in b the game will be unfair.
Extension
Experiment with four or more sections to see what fair and unfair spinners you can make.