Here’s a trick that will make your friends think you can guess any number they think of.
-Choose a number between 0 and 50 and write it down on a piece of paper. Fold the paper and give it to a friend who mustn’t look at it.
-Ask your friend to choose a number between 50 and 100. He mustn’t let you know what it is.
-Subtract the number you had chosen (and written on the piece of paper) from 99.
-Ask your friend to add the result you get to the number he chose.
-He must then take off the first digit on the left and add it to the number.
-Then, ask him to subtract this number from the one he had originally chosen.
The resulting number will be the one you had written on the paper at the very beginning!