George Boole

Largely self-taught, he turned logic into algebra in The Laws of Thought (1854).

Every digital circuit runs on his true-and-false arithmetic. He was the first professor of mathematics at Queen’s College, Cork.

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.