Let us do a fun activity. Take three piles of cards - one with 11 cards, second with 7 cards and the third with 6 cards and place them on a table.
The challenge is to move cards in a manner that each pile has 8 cards by the time you are done.
The rules are:
1) You can add to any pile but you must add exactly the amount of cards the pile already has. Suppose that a pile has 7 cards, then you will have to move exactly 7 cards from another pile to keep above it.
2) All cards should be taken from the same pile at one time.
3) You have only 3 moves.