The Power of Doubling

An ancient legend tells of a chess player who asked a king for one grain of rice on the first square, two on the second, four on the third — doubling each time. The king agreed, thinking it a small reward. By square 64, the total would be 18 billion billion grains — more than all the rice ever grown. That is exponential growth: slow at first, then exploding. It describes population growth, compound interest, radioactive decay, and the spread of diseases — all from the deceptively simple equation y = aˣ.