Rice and chessboard problem
Legend tells that the inventor of game of chess was asked by the emperor to name their own reward – the inventor asked for one grain of wheat to be placed on the first square of the chessboard, two grains on the second and so on, placing double the number of grains on each subsequent square.
The emperor happily granted this meagre reward, thinking it would amount to just a few handfuls of wheat! This proved to be an expensive mistake…
More information about this classic mathematical problem can be found on Wikipedia.
Chessboard image By McGeddon, from Wikimedia Commons CC BY-SA 4.0