One: Fourier said: "The main goal of mathematics is the public interest and the explanation of natural phenomena".

Two: Klein (American mathematician) said: "Mathematics is a rational spirit, which can make human thinking apply to the most perfect degree."

Three: Laplace said: "In mathematics, the main tools for us to find truth are induction and simulation".

Four: Some beautiful theorems in mathematics have such characteristics: they can be easily summarized from facts, but the proofs are extremely profound.

Five: Mathematics is the queen of science and number theory is the queen of mathematics. Gauss music can inspire or soothe feelings, painting can make people pleasing to the eye, poetry can impress people, philosophy can make people gain wisdom, science can improve material life, but mathematics can give them all. Klein