Pisa and the Mediterranean · c. 1170-after 1240
Fibonacci
Pronunciation: fee-boh-NAH-chee
A Pisan mathematician whose Liber Abaci promoted efficient calculation with Hindu-Arabic numerals for trade, conversion, interest, and mathematical problems.
Fibonacci’s surviving books document his mathematical work; many personal details and exact dates remain uncertain.
3-5, 6-8, 9-12
The person and the work
Biography
Leonardo of Pisa, later called Fibonacci, learned calculation methods while traveling around the Mediterranean world in connection with his father’s commercial work.
His Liber Abaci explained the practical value of the Hindu-Arabic numeral system and included problems about exchange, profit, mixtures, interest, and sequences.
Mathematical contribution
What this hero added or preserved
Practical numeral calculation
Fibonacci showed European readers how place-value numerals and written algorithms could simplify commercial arithmetic.
A memorable sequence problem
A rabbit-growth problem in Liber Abaci produced the sequence now associated with his name, though the sequence was known in Indian mathematics earlier.
Why this matters
The larger lesson
The best number system is not merely a set of symbols. It changes how quickly people can calculate, check work, teach procedures, and manage real transactions.
Place the work in time
Timeline
- 1202
Liber Abaci appears
Fibonacci presents calculation methods and practical problems using Hindu-Arabic numerals.
- 1228
A revised edition circulates
The work is revised and continues influencing European arithmetic.
Key idea
Recursive sequences
A recursive sequence defines later terms using earlier terms.
Starting 1, 1 and adding the two previous terms gives 1, 1, 2, 3, 5, 8, 13.
Try it yourself
Continue and explain a sequence
Continue 2, 3, 5, 8, 13 for three more terms and state the rule.
- Add the two most recent terms.
- Repeat with the newest pair.
Show the answer
21, 34, 55; each term is the sum of the previous two.
Math at work
Commerce depends on trustworthy calculation
Currency conversion, price, tax, inventory, credit, interest, and profit all require consistent numerical methods.
Keep curiosity alive
A little-known fact
The nickname Fibonacci was adopted centuries after Leonardo’s lifetime.
Fibonacci discovered the famous sequence from nothing.
His rabbit problem popularized it in Europe, while related sequences had appeared earlier in Indian mathematical work.
Keep exploring
Connected learning paths
Related math terms
- Recursive sequence
- Place value
- Compound interest