Think of a number between 1 and 100. Say nothing. Others guess one at a time and receive only 'higher' or 'lower.' Seven guesses to find it. Most players figure out the optimal strategy on their own after a few rounds. For younger children, use 1 to 20.

How to do it

1One player thinks of a number between 1 and 100. Says nothing.
2Others guess, one at a time. After each guess: higher, or lower. Nothing else.
3Seven guesses to find it. First correct answer becomes the next picker.
4For under-sixes, use 1 to 20. The optimal strategy reveals itself — let them find it.

Variations

If they give up early, offer hints — 'you're warmer' or 'think smaller' — maintains engagement.
How it ends: when guessed, celebrate and move to the next guesser immediately — the game resets naturally.

💡 Parent tip

After a few rounds, ask: 'What would happen if you always guessed the number in the middle of the remaining range?' Most children have already noticed this works. The question makes explicit what they've been intuiting — and that moment is a genuine mathematical discovery.

What your child develops

Binary search intuition — the optimal strategy of always guessing the midpoint emerges through play, not instruction
Number line internalisation — 'higher' and 'lower' require a mental image of where numbers sit relative to each other
Logical deduction — using two pieces of information together to narrow the range is applied reasoning