Wheat and chessboard problem

Uncommon card · No. 151294

The wheat and chessboard problem (sometimes expressed as the rice and chessboard problem) is a mathematical problem expressed in textual form as: If a chessboard were to have wheat placed upon each square such that one grain were placed on the first square, two on the second, four on the third, and so on (doubling the number of grains on each subsequent square), how many grains of wheat would be on the chessboard at the finish? The problem may be solved using simple calculation. With 64 squares on a chessboard, if the number of grains doubles on successive squares, then the sum of grains on all 64 squares is: 1 + 2 + 4 + 8 + ... and so forth for the 64 squares. The total number of grains can be shown to be 264 − 1 or 18,446,744,073,709,551,615 (eighteen quintillion, four hundred forty-six quadrillion, seven hundred forty-four trillion, seventy-three billion, seven hundred nine million, five hundred fifty-one thousand, six hundred and fifteen). This exercise can be used to demonstrate...

Read on Wikipedia · Image McGeddon, CC BY-SA 4.0