Mathematics
c. 1170 to c. 1245, Pisa, Italy
The merchant’s son who carried Hindu-Arabic numerals into Europe, gave his name to a famous sequence, and did real number theory in the Book of Squares.
Start learning Leonardo →How a Pisan merchant’s son who learned ‘the nine figures of the Indians’ and the sign for zero in a North African port wrote the book that taught Europe to calculate with place-value numerals, and why…
The playful breeding puzzle Fibonacci posed in the Liber Abaci - how many rabbit pairs in a year? - and the sequence it generates: 1, 1, 2, 3, 5, 8, 13..., governed by the rule that each number is the sum of the two bef…
The real mathematics linking the Fibonacci sequence to the golden ratio - the ratio of consecutive terms converging on phi (about 1.618) - done honestly, together with a clear-eyed debunking of the exaggerated ‘go…
The Liber Abaci as a working manual for merchants - currency conversion, profit and interest, barter, and the all-purpose ‘rule of three’ - and how the new arithmetic became a driving force of the medieval c…
Fibonacci’s masterpiece, the Liber Quadratorum (Book of Squares, 1225), on congruent numbers and sums of squares; the mathematical contest before Emperor Frederick II that provoked it; and the case that Fibonacci…
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