A French Mathematician concealed his proficiency with differential equations to avoid working for the Nazis. While in a POW camp, he developed sheaves, sheaf cohomology, and spectral sequences which are important tools for modern Algebraic Geometry.
Mathematician John Edmund Kerrich passed his time in Nazi captivity by flipping a coin 10,000 times. The total percentage of heads and tails flips varied wildly at first but gradually converged around 50/50, providing a demonstration of the Law of Large Numbers.
Chinese mathematician Yitang Zhang could not get an academic job upon graduating, having to work as an accountant and a delivery worker for a New York City restaurant. He later went on to solve a math problem that had been unsolved for 150 years and won a MacArthur Genius Grant.
Grigori Perelman, a Russian mathematician, successfully proved the Poincaré conjecture (one of the seven Millennium problems) in papers made available in 2002 and 2003. When his work survived review, he was offered a Fields Medal and the $1,000,000 Millennium Prize, both of which he turned down.
When Grigori Perelman, a Russian mathematician, solved the most important problem in topology he was awarded the Fields Medal and Millennium Prize of one million dollars. He declined both saying: “The main reason is my disagreement with the organized mathematical community. I don’t like their decisions, I consider them unjust.”
Mathematician Zachary Harris hacked into Google’s email system and sent a e-mail phishing attack to Larry Page from Sergey Brin’s e-mail account. All because he noticed a flaw in an e-mail sent from Google offering him a job and thought it was a test. It wasn’t.
The French mathematician, Abraham de Moivre, predicted the date of his own death by noticing he slept an extra 15 minutes each day.
When the mathematician George Dantzig was studying in Berkeley, he solved two open problems in statistical theory which he had mistaken for homework after arriving late to a lecture.
The Fibonacci Sequence was described by an Indian mathematician ~1200 years before Fibonacci wrote of it.
Humans actually knew the earth was round as early as 2500 years ago. Eratosthenes calculated the circumference of the planet to an astounding accuracy of around 99%.