The Shah's chessboard
The man who invented chess asked for wheat instead of gold. The Shah laughed and said yes.
One grain on the first square, two on the second, four on the third, doubling every square to the sixty-fourth. How much wheat is on the LAST square?
Where these numbers come from
One wheat grain weighs roughly 35 milligrams, so about 28 600 grains make a kilogram.
Wheat: Grain weight and grain number — USDA Agricultural Research Service(checked 2026-09-16)The world grows about 800 million tonnes of wheat a year — roughly 23 000 000 000 000 000 grains.
Crops and livestock products: wheat production — FAOSTAT, Food and Agriculture Organization of the United Nations(checked 2026-09-16)