Willem Klein

https://en.wikipedia.org/wiki/Willem_Klein

Willem Klein (4 December 1912 – 1 August 1986), also known as Wim Klein or under his stage names Pascal and Willy Wortel, was a Dutch mathematician, famous for being able to carry out very complicated calculations in his head very fast. On 27 August 1976, he calculated the 73rd root of a 500-digit number in 2 minutes and 43 seconds. This feat was recorded by the Guinness Book of Records.

Wim Klein was born in Amsterdam, Netherlands on 4 December 1912 to Henry Klein, GP, and Emma Cohen. Klein had a rough childhood because his father wanted him to become a Doctor (as his father was), even though he was quite opposed to the idea. In addition to this pressure, his mother also committed suicide in 1929. In 1932, when Klein finished High School, despite wanting badly to pursue his love of mathematics, he gave in to his father's demands and enrolled at the University of Amsterdam for Medicine; he succeeded in getting his bachelor's degree in 1935.