There is a birthday party with 6 invited children. At the party a piñata is prepared with 21 goodies inside. When they break the piñata, the children run to collect their goodies. In the end each one gets a different number of goodies.
How many goodies has each child got?
The first child has got 1 candy, the second 2, the third 3, the fourth 4, the fifth 5 and the sixth 6, or 21 in total.