The Impossible Guess

At first you might think this game would take ages - but with practice you should be able to finish it very quickly! All that happens is that the computer thinks of a TARGET number and you have to guess what it is.

• Decide how hard you want to make the game by choosing the lowest and highest numbers that the computer can choose a target number from. For a very easy game, put "0" in the FROM box and put "20" in the TO box. Then click "start" and the computer will think of a number.
• Now type your first guess in the bottom box and click "guess". The computer will tell you if the target number is higher or lower than your guess.
• Keep going until you get it!

How good are you?

If you set the range from 0 to 100, you should be able to hit the target with 7 guesses or less.

If the range is from 0 to 1,000, how many guesses do you think you should need?
As the range is ten times bigger, you might think you need 70 guesses! In fact you should be able to hit the target with 10 guesses or less.

If your range goes from 0 to 1,000,000 you should only need 20 guesses!