Arithmetic for merchants
Liber abaci explained place-value numerals and calculations useful in trade. Fibonacci helped spread methods he learned through Mediterranean mathematical traditions.
30 / ANTIQUITY TO THE RENAISSANCE
Leonardo of Pisa (Fibonacci)
One pair of rabbits, a wall, and a rule for breeding. How many pairs after a year?
Explore the mathematics ↓
01 / THE RABBIT SEQUENCE
Where does the next number come from?
A pair has a pair of young every month. Young pairs start breeding in their second month.
Every pair from last month is still there, and each pair from two months ago has one newborn.
=
=
THE IDEAThis month’s total = last month’s total + the total two months ago. Fibonacci’s own working reaches 1, 2, 3, 5, 8, … and 377 pairs at the end of the year.
The person behind the ideas
- Learned mathematics in North Africa.
- Wrote Liber abaci in 1202 and revised it in 1228.
- Also made substantial contributions to number theory.
More of the mathematics
Beyond the rabbits
His Book of Squares studied number-theoretic questions, including relationships between square numbers.