Fibonacci was an Italian mathematician in the Middle Ages, the first person to study Fibonacci numbers in the West, and introduced the modern system of writing numbers and multipliers to Europe. In the book Calculation, he put forward the problem of rabbit growth rate under an ideal hypothesis and solved it himself. The number of rabbits in each generation can form a series, which is Fibonacci number, but Leonardo was not the first mathematician to mention the series, which was first discovered by Indian mathematicians in the 6th century.

Fibonacci has made remarkable achievements in the field of mathematics. One of his most important contributions was the discovery of Fibonacci sequence, which was not widely accepted at that time, but later became an important branch of mathematics. In addition, he also studied the golden section, helix and other issues, and made important contributions to probability theory and geometry.

First of all, Fibonacci sequence is a typical infinite sequence, and its definition is very simple, that is, each number is the sum of the first two numbers. However, this series has many peculiar properties, such as the golden ratio and periodicity. These properties are widely used in mathematics, physics, engineering and other fields, such as computer graphics, biology, economics and so on.

Secondly, Fibonacci also studied the golden section, helix and other issues. The golden section is a universal proportional relationship in nature and has important applications in architecture, painting, design and other fields. Spiral is a common curved shape in nature, such as snail shell and DNA molecule. Fibonacci's research on these problems provided inspiration for later mathematicians and promoted the development of mathematics.

Finally, Fibonacci also made important contributions to probability theory and geometry. His book Arithmetic contains many contents about probability theory, such as "Pisa Theorem" (the results of two consecutive coin flips do not affect each other). In addition, he also studied curves and surfaces in geometry, such as Jacobian matrix and Bezier curve.

In a word, Fibonacci's achievements in the field of mathematics are very rich, and his research results have had a far-reaching impact on later mathematicians. His contribution is not only reflected in specific mathematical problems, but also provides a new perspective and method for the development of mathematics. Therefore, Fibonacci is known as the "king of mathematicians" and one of the greatest mathematicians in the history of mathematics.