 ##### Where the World Gathers to Celebrate Every Day # FIBONACCI DAY – November 23

## FIBONACCI DAY

Every November 23rd, Fibonacci Day honors Leonardo Bonacci, one of the most influential mathematicians of the Middle Ages. The date corresponds to the first numbers of the Fibonacci sequence  – 1 1 2 3.

Fibonacci is an Italian mathematician who is also known as Leonardo of Pisa and Leonardo Fibonacci. Some say Fibonacci invented the Fibonacci sequence. This pattern of counting means that each number is the sum of the previous two. (0,1,1,2,3,5,8,13, etc.) Computer data storage and processing uses this number sequence today. The sequence is also useful in the trading of stocks and architecture. Another unexpected place we find the sequence is in nature. DNA patterns and hurricanes contain patterns showing this sequence. Math and science classes refer to the Fibonacci sequence as “nature’s secret code” or “nature’s universal rule.” Additionally, the number sequence is tied to the golden ratio and the golden triangle.

The Fibonacci numbers were published in his book, Liber Abaci in the year 1202. Fibonacci’s book introduced the Western World to the Hindu-Arabic numeral system we use today. This numeral system writes numbers as 1,2,3, etc. instead of Roman numerals I, II, III, etc.

Fibonacci was born in 1170. As a young boy, he traveled with his father, an Italian merchant named Guglielmo. During his travels, he learned about the Hindu-Arabic numeral system. As he traveled around the Mediterranean Coast, Fibonacci met with merchants and learned their arithmetic systems. In the 19th century, the city of Pisa erected a statue of Fibonacci. Today it stands in the western gallery of the Camposanto.

### HOW TO OBSERVE #FibonacciDay

Math and science classes around the world hold a variety of fun activities utilizing the Fibonacci sequence. To participate:

• Watch a video showing the Fibonacci sequence in nature or a video discussing the magic of Fibonacci numbers.
• Look for items in your home or nature containing the Fibonacci sequence.