The chess and the grains of rice

To occupy a dull day, the King promised great fortune to anyone who invented a game. Many games were presented, but the winner was the one who created chess. When the time came to receive the prize, the winner refused his prize and asked the King to give him only grains of rice, which should be counted as follows: one grain of rice on the first square of the game board, two on the second square , four in the third, eight in the fourth, and always doubling the amount until the sixty-fourth and last square. The King readily accepted as he thought the request would translate into just a few pounds. However, at the end of the count, the king's mathematician, desperate, told him that it would take several years of cereal production for the debt to be paid off. To help you have a dimension of how many grains of rice there would be, we will calculate: Number of grains: 1 + 2 + 4 + 8 + … up to the 64th square This is equivalent to: (2⁶⁴) – 1 Neglecting a grain, 2⁶⁴ is equal to 18,446,744,000,000,000,000 grains. With this amount of grains, we have: 439,208,190,000 tons of rice. ; The total estimated production of rice in the world in 2022 was 503,000,000 tons, that is, to pay off the debt, it would take 873 years. What does this story have to do with investments? It is a classic example of compound interest. Compound interest can be an excellent strategy for the investor, as the initial amount invested grows exponentially.