Leonardo Fibonacci
Leonardo Fibonacci was born in Pisa, Italy around 1175 to Guilielmo Bonacci.

Leonardoís father was the secretary of the Republic of Pisa and directed the

Pisan trading colony. His father intended on Leonardo becoming a merchant. His
father enlisted him in the Pisan Republic, sending him to various countries. As

Leonardo continued to travel with his father, he acquired mathematical skills
while in Bugia. Fibonacci continued to study throughout his travels, which ended
around the year 1200. Leonardo began writing books on number theory, practical
problems of business mathematics, surveying, advanced problems in algebra and
recreational mathematics. Leonardoís recreational problems became known as
story problems and became mental challenges in the 13th century. Of all the
books he wrote we still have copies of Liber abbaci (1202), Practica geometriae
(1220), Flos (1225), and Liber Quadratorum. Sadly his books on commercial
arithmetic Di minor guisa is lost as well as his commentary on Book X Euclidís

Elements. One of Leonardoís contributions to mathematics was his introducing
the Decimal Number system into Europe. He was one of the first people to
introduce the Hindu-Arabic number system into Europe. Fibonacci also introduced
the Decimal Positional System, which originated from India and Arabia. Fibonacci
wrote story problems in his book, Liber abbaci. Examples of those problems are,

"A spider climbs so many feet up a wall each day and slips back a fixed number
each night, how many days does it take him to climb the wall. These problems
became quite popular. Another accomplishment was his forming the Fibonacci

Series. It is a series of number in which each member is the sum of the two
preceding numbers. For example, a series beginning 0, 1 ... continues as 1, 2,

3, 5, 8, 13, 21, and so forth. The exact period of this discovery is not known.

Leonardo was a bright man, but left much of his solutions to his questions or
problems without explanations. No way for some finding how he arrived at it.

During Leonardoís lifetime he was recognized for his efforts and contributions
to mathematics. In 1225 Holy Roman Emperor Fredrick ll recognized Leonardo for
his work. In 1240 the Republic of Pisa awarded Fibonacci a salary for his work
as well. It is not known for sure, but Leonardo is said to have died sometime
after he received his salary. His many contributions are well remembered today
by people in the math community.