Who the seven mathematicians are

Syracuse, 3rd century BCE. We owe him the principle that bears his name, a remarkable approximation of π, and machines that defended his city.

To tell in class: he is said to have found, in his bath, how to check whether a crown was pure gold, and to have run out shouting “Eureka!” The first mathematician an eight-year-old remembers.

Ada Lovelace, London, 1815-1852. She wrote the first program in history, for a machine that was never built in her lifetime.

To tell in class: she understood before anyone else that a machine for numbers could one day compose music. The computer did not exist yet.

Srinivasa Ramanujan, India, 1887-1920. Self-taught, he rediscovered major results on his own, then found thousands more.

To tell in class: one day, a colleague told him that his taxi number, 1729, was quite dull. Ramanujan replied at once that it is the smallest number that can be written as the sum of two cubes in two different ways.

Émilie du Châtelet, France, 1706-1749. She translated and commented on Newton’s work in French, and her translation is still the reference.

To tell in class: to enter a Paris café reserved for men where science was discussed, she showed up dressed as a man.

Baghdad, around 780-850. His name, altered in Latin, gave us the word “algorithm”. The title of his book gave us the word “algebra”.

To tell in class: he solved equations with no symbols at all, only with sentences and drawings of squares. The letter x did not exist yet.

Emmy Noether, Germany, 1882-1935. Her theorem links the symmetries of nature to the conservation laws of physics.

To tell in class: Einstein considered her the most important mathematician of her time. For years, she taught at the university without being paid.

Henri Poincaré, France, 1854-1912. The last person to have mastered all the mathematics of his time, and one of the founders of chaos theory.

To tell in class: he said he found a major idea as he was stepping onto a bus, after weeks of not thinking about it. He drew from that a theory of how discoveries are born.