Fibonacci

Leonardo of Pisa (c. 1175-1250), also known as Fibonacci, was an Italian mathematician and is best known for the invention of the Fibonacci numbers and his role in the introducton of the Hindu numerals to Europe.

Leonardo's father was nicknamed Bonacci ('good natured') and Leonardo was therefore known as Fibonacci (filius Bonacci is "son of the good natured one"). Bonacci may also mean 'simpleton'. The father of Leonardo directed a trading post (by some accounts he was the consul for Pisa) in Bugia, North Africa (now Bejaia, Algeria), and as a young boy Leonardo traveled there to help him. There he learnt from the Arabs the Indian numeral system.

Perceiving the superiority of these so-called Arabic numerals, Fibonacci travelled throughout the Mediterranean world to study under the leading Arab mathematicians of the time. In 1202, at age 27, he published what he had learned in Liber Abaci, or Book of the Abacus. This book showed the practical importance of the new number system by applying it to commercial bookkeeping, conversion of weights and measures, the calculation of interests, money-changing, and numerous other applications. The book was enthusiastically received throughout educated Europe and had a profound impact on European thought.

Important Publications

• Liber Abaci, a book on calculations.
• Practica Geometriae, a compendium on geometry and trigonometry.
• Liber quadratorum, (The Book of Squares) on Diophantine problems, that is, problems involving Diophantine equations.