9. Mathematics is a variety of proof skills. 10, new mathematical methods and concepts are often more important than solving mathematical problems themselves. The story of mathematician Hua The famous mathematician Hua Yu 1946 was hired to give lectures in the United States, which was highly valued by the academic community. At that time, the University of Illinois signed a lifelong faculty contract with him, with an annual salary of 1 10,000 dollars. Life in China suddenly became comfortable. Not only does he have a small building, but the university has specially equipped him with four assistants and a typist. After the founding of New China, some people always thought that China had become famous in the United States, lived a comfortable life and would never come back. However, material, money and status did not bind his patriotism. 1950 In February, Hua resolutely gave up the treatment of Professor Guo in the United States, broke through the blockade and returned to the motherland. When passing through Hong Kong, he wrote an open letter to students studying in the United States, expressing his enthusiasm for dedicating himself to the motherland. He warmly appealed: "For the sake of the country and the nation, we should go back!" "Although Chengdu is happy, it is better to go back to your hometown; Although Liangyuan is good, it is not a place to stay for a long time. "