# Leonardo Pisano Fibonacci

## Who He Is

Leonardo Pisano, otherwise known as Fibonacci, was born in 1170 in what historians believe to be Pisa, which is now Italy. He died in 1250 in what is believed to be Pisa as well.

He grew up in North Africa, and afterwards travelled extensively around the mediterranean coast. After learning the merchants ways of arithmetics, he discovered that the Hindu-Arabic system worked the best over all others.

He has become one of the best mathematicians of all time.

## His Mathmatical Contributions

He was the first to introduce the Hindu-Arabic system of numerals to Europe, which is the one we use today.

Leonardo wrote a book that is roughly translated to The Book Of Calculating. It explains how to use the new system, which convinced many mathmaticians of his time to use the new system. It uses the subtraction, division, adding, and multiplying that we do now.

The most famous thing he is known for is the Fibonacci Sequence. He did not discover it, as it was known in India much before, but he introduced it to Europe. The Fibonacci Sequence is a series of numbers:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...

And so on. You find the next number by adding the two numbers before it. Therefore, it is infinite. If you look at it in a spiral pattern, it is neat, which I will show you in a second.

If it is written as a rule, it would be:

x

n

= x

n-1

+ x

n-2

The Fibonacci sequence is very similar to the golden ratio.

It is also found in nature.