Leonardo Pisano, known most of his life as Fibonacci. Wrote LiberAbaci (Book of the Abacus) around AD MCCII, making folks aware that Hindu-Arabic numeric symbols could be used as a powerful substitution for clumsy letter based systems of numbering. Best known for solving the problem of how many rabbits will be born in one year, starting with one pair and assuming that each month each pair produces another pair (which can begin to breed in two months). See FibonacciSequence. ---- FiboNacci would be etymologically more accurate. ''Would it? I think Fibonacci comes from "son of Bonaccio", in which case FiBonacci would be a better break down.'' ---- And what about the mathematician BiNomi, who wrote a book about elementary algebra around 1331. The well known binominal theorem is named after him. ''Has someone's watch stopped? It's not April 1st today.'' ---- CategoryScientist