# Fibonacci Numbers

Pronunciation: /ˌfib.oʊˈnɑ.tʃi ˈnʌm.bərz/ Explain

Fibonacci numbers
NumberCalculation
0Defined as 0
1Defined as 1
10 + 1 = 1
21 + 1 = 2
31 + 2 = 3
52 + 3 = 5
83 + 5 = 8
135 + 8 = 13
218 + 13 = 21
3413 + 21 = 34
5521 + 34 = 55
...
Table 1: Fibonacci numbers

Fibonacci numbers are a sequence of numbers starting with 0, 1. After the first two numbers, each number in the sequence is calculated by adding the two previous numbers. See table 1.

Fibonacci numbers were first described in (asiatic) Indian mathematics. However, they are named after Leonardo de Pisa [c. 1170 – c. 1250] who introduced them to the western world in his book Liber Abaci (Book of Calculation). Leonardo de Pisa is also know as Fibonacci (son of Bonacci).

The Fibonacci numbers have some interesting properties. Figure 1 shows a sequence of squares. The length of the side each square is one of the Fibonacci numbers. These squares form a rectangle that grows with each Fibonacci number. Figure 1: Fibonacci Squares
1. McAdams, David E.. All Math Words Dictionary, fibonacci numbers. 2nd Classroom edition 20150108-4799968. pg 79. Life is a Story Problem LLC. January 8, 2015. Buy the book
2. Fibonacci numbers. merriam-webster.com. Encyclopedia Britannica. Merriam-Webster. Last Accessed 7/11/2018. http://www.merriam-webster.com/dictionary/fibonacci numbers. Buy the book
3. Laurence Sigler. Fibonacci's Liber Abaci. Springer. November 11, 2003. Last Accessed 7/11/2018. Buy the book
4. Alfred S. Posamentier and Ingmar Lehmann. The Fabulous Fibonacci Numbers. Prometheus Books. June 21, 2007. Last Accessed 7/11/2018. Buy the book
5. Nicolai N. Vorobiev and M. Martin. Fibonacci Numbers. Birkhäuser Basel. January 31, 2003. Last Accessed 7/11/2018. Buy the book

### Educator Resources

McAdams, David E. Fibonacci Numbers. 12/21/2018. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/f/fibonaccinumbers.html.

### Revision History

12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)