A basket contains 5 apples. Do you know how to divide them among 5 kids so that each one has an apple and one apple stays in the basket?
There are a few trees in a garden. On one of them, a pear tree, there are pears (quite logical). But after a strong wind blew, there were neither pears on the tree nor on the ground. How come?
13 people came into a hotel with 12 rooms and each guest wanted his own room. The bellboy solved this problem. He asked the thirteenth guest to wait a little with the first guest in room number 1. So in the first room there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the twelfth guest to room number 11. Then he returned to room number 1 and took the thirteenth guest to room number 12, still vacant. How can everybody have his own room?