When the creator of the game of Chess showed his invention to the ruler of the country, the ruler was so pleased that he gave the inventor the right to name his prize for the invention. The man asked the king a grain of rice for the first square of the chess board, two grains for the second square, four grains for the third square and so forth, doubling the amount of grains for each square.
The ruler, arithmetically unaware, quickly accepted the inventor's offer, even getting offended by his perceived notion that the inventor was asking for such a mere trifle, and ordered the treasurer to count and hand over the rice to the inventor. However, when the treasurer took more than a week to calculate the amount of rice, the ruler asked him the reason for his tardiness. The treasurer then gave him the result of the calculation, and explained that it would be impossible to give the inventor his reward.
The reason for this situation, known in Mathematics as exponential sequence, is that the total number of grains on the chessboard would be:
1 + 2 + 4 + 8 + 16 + ... = 264 − 1 = 18,446,744,073,709,551,615 = 18 x 1018
which would be a heap of rice larger than Mount Everest weighing more than 461 billion tons.
A mere trifle...