Statistics and Probability Use groups of 2. Materials: Grid paper

Riddled Grid

Use grid paper to make two game boards like the one shown below. Each partner then takes a game board and secretly shades at least ten squares.

One partner names ten squares on the other partner's game board by giving coordinates such as A7 or B2. The other partner tells how many of these ten squares are shaded. Trade roles and repeat the procedure. Then use the number of shaded squares out of ten to predict the total number of squares your partner shaded. Trade papers to see how close your prediction was.