This story is an old Indian folk tale. A certain king loved new games that could be used to entertain. Once an old man came to him and presented a board with 64 squares. The old man showed the king how to play using some figurines. Well you guessed it. It was the game of chess, a game of intelligent, logical moves. The enthralled king asked the old man to claim his prize. the old man said "Well give me two grains of rice for the first square, four for the next , eight for the next, 16 for the fourth square and so on.The king felt insulted, "What is this pittance that you ask for? I am the mighty king of the state of Benaras, the richest of all the kingdoms here and all you ask of me is a few grains of rice?" "No my king, just give me what I ask you" replied the old man. The king asked his servants to fulfil the demands of the old man. Well the first few squares were fine but as they proceeded, the king's granaries did not have enough rice to fill the squares. Infact by the 30th square the granaries were empty.The king now saw what a genius the man was and humbly joined his hands and bowed before the man. Well are you really interested in knowing how many grains the board required in all? About 18 billion grains.A 100 pound rice bag has less than three billion grains.
The story is a good one to introduce the concept of powers of a number.