This activity is best played in pairs.

Child A thinks of a number. They state a range in which their number can be found, e.g. "My number is between 0 and 100" or "My number is between 250 and 500".

Child B has to ask Child A questions in order to find out the number, but A can only reply using "Yes" or "No" answers.

For example...

Child A: My number is between 50 and 150

Child B: Is it less than 100?

Child A: Yes.

Child B: Is it more than 75?

Child A: No.

And so on...

The children could count the number of questions that they each asked, seeing who found the mystery number in the lowest number of questions.