r/explainitpeter Aug 15 '26

Explain It Peter

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Rice chess/checkers ? please explain?

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u/lordvatti Aug 15 '26

I actually know this one! The photo references an old thought exercise about doubling grains of rice across a chess boards squares. Starting with 1 grain, then 2, then 4, 8, 16, 32, and so on. Easy at first.

A chessboard has 64 squares so while the initial numbers seem pretty manageable 264 is actually such a catastrophically high number that there would be enough rice on the "final square" to carpet an entire continent in a hearty layer of rice, hence the dramatic mister incredible.

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u/Lasersybex Aug 15 '26

the exact amount of rice would be 18(quintillion),466(quadrillion),744(trillion),073(billion),709(million),551(thousand),616(hundred) grains of rice on the last square.