Leonardo Fibonacci was one of the great mathematicians of his time. His lifestyle allowed him to travel and study math in various countries, and he ended up combining his cultural knowledge to discover the most effective ways of doing mathematics. He is most famous for his contributions to the European number system and for his sequence of numbers known as the Fibonacci numbers. Starting with 0 and 1 as the first two numbers, each number in the sequence is the sum of the two preceding numbers. He came across these numbers as a solution to a problem that he used as an example in one of his many publications. He was not aware of the importance of his findings at the time. Many uses have been found for these numbers since Leonardo’s death and many mathematicians have used this sequence in their own theories.
Leonardo Fibonacci was born in Pisa, Italy in the middle 1170’s. When he was almost twenty, he moved to Bugia, Algeria with his father, Guielmo Bonacci. Bonacci was the secretary of the Republic of Pisa responsible for directing the Pisan trading colony in Bugia. When he brought his son to Algeria, he had Leonardo educated to become a merchant. During his studies in northern Africa, Fibonacci discovered the Hindu-Arabic number system, which he had not been exposed to in Europe. When his father arranged for him to work for the Pisan republic, Leonardo took advantage of his business trips to countries such as Greece, Sicily, Egypt and Provence. He studied the methods of mathematics that were practiced in these various nations. He discovered that the Hindu-Arabic numerals were much more effective and easier to manipulate than the Roman numeral system used in Italy. [i]
Fibonacci returned to his hometown of Pisa around 1200. There, he spent many years working on his five major mathematical publications. [ii] The first of his works was entitled Liber abbaci, (meaning “Book of Calculating,”) and was published in 1202. The book is an explanation of the use of the number system that Fibonacci learned in Algeria. It describes the base ten system that uses nine characters: 1, 2, 3, 4, 5, 6, 7, 8, and 9, as well as a tenth character of value zero: 0. Fibonacci goes on to explain the use of the decimal point and the meaning of the character placement in a number. He illustrates the operations of adding, subtracting, multiplying and dividing, using various examples to explain his methods. He shows that numbers can be summed by lining up the columns and adding, or subtracting, vertically, carrying values of ten. He thoroughly describes the methods used to multiply and divide the numbers as well. This book was one of the first exposures that Europe had to this new system, and it proved to be persuasive, causing many Europeans to convert to this system.[iii]
Fibonacci published four other distinguished works that we know of. The first is a letter referred to...