From India
Bhaskara II
He called his arithmetic book Lilavati; a legend says it was written for his daughter. It teaches through puzzles about bees, peacocks and pearls.
In his Bijaganita he solved x² − 61y² = 1, whose smallest answer has a 10-digit x, using the cyclic chakravala method.
Smallest solution: x = 1766319049, y = 226153980
No portrait of Bhaskara II survives, so we show the mathematics instead.
Where you’ll meet II here
AlgebraNumber theoryCounting
They turn up beside problems and lessons on these topics.
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Shakuntala Devi
Known as the “human computer”, in 1980 at Imperial College London she multiplied two 13-digit numbers in her head in 28 seconds.
She also wrote popular books of puzzles and mental arithmetic.
Central News Agency (Taiwan), Public domain, via Wikimedia Commons