Number guessing game – Up/Down, find the number

This number guessing game, also called an up and down game, hides a whole number and lets you find it with as few guesses as you can.

Choose a range of 1 to 50, 1 to 100 or 1 to 1000, type a guess and press the button.

The game answers UP if the hidden number is bigger than your guess and DOWN if it is smaller, and it keeps showing the range that is still possible, so you can always see how far you have narrowed it down.

How can I guess faster? Use the halving method: always guess the number in the middle of the remaining range.

In a range of 1 to 100 you can always find the answer in seven guesses or fewer, in 1 to 50 in six or fewer, and in 1 to 1000 in ten or fewer.

For example, if the range is 1 to 100, guess 50; if the answer is UP the range becomes 51 to 100, so guess 75 next. Is the number really random? Yes.

It is chosen with your browser's secure random generator, so no number is more likely than another and the game cannot change it while you play. Where is my record kept?

The fewest tries for each range is saved only in this browser on this device, and nothing is sent anywhere.

The game works well as a quick way to teach children the idea of narrowing down, as a car ride game, or as a short break. It is just for fun, so there are no prizes and nothing is wagered.

When you finish, share your tries with a friend and see who needs fewer. You may also like the mental math game or the tic tac toe game.