Zu Chongzhi was an outstanding mathematician and astronomer in the Southern and Northern Dynasties. In Zu Chongzhi's time, abacus did not appear, and the commonly used calculation tool was called calculation. It is a square or flat stick several inches long, made of bamboo, wood, iron, jade and other materials. ?

Different calculation and financing methods are used to represent various numbers, which is called financing algorithm. If there are more digits, the larger the area needs to be placed.

It is not like using a pen to calculate with a calculation formula, it can be left on paper, and every time the calculation is completed, it must be swung again for a new calculation; You can only write down the calculation results with notes, and you can't get more intuitive graphics and formulas.

So as long as there are errors, such as calculation errors or calculation errors, we can only start from scratch.

In order to get the accurate value of pi, Zu Chongzhi needs to calculate the decimal of nine significant figures, including more than ten steps of addition, subtraction, multiplication, division and square root operation, and each step has to be repeated for more than ten times and 50 times of square root operation, and finally the calculated number reaches 16 or 17 digits after the decimal point.

2. Hua's wonderful story

Hua is an academician and mathematician of China Academy of Sciences. 1953, China Academy of Sciences organized a delegation to go abroad, headed by scientist Qian Sanqiang. Members include Hua, Zhao Jiuzhang and Zhu Xian. In his spare time, Hua wrote a couplet: "The top three are Korea, Zhao and Wei", seeking this couplet. ?

The "top three" here refers to Korea, Zhao and Wei San during the Warring States Period, but it implies the name of the head of the delegation, Comrade Qian Sanqiang, which not only solves the traditional difficulty of the couplet of numbers and numbers, but also requires the name of another scientist to be embedded in the bottom couplet.

After a while, when Hua saw that everyone had no bottom line, he revealed his bottom line: "Hook, strand and string are nine chapters." Nine Chapters is a famous mathematical work in ancient China.

However, the "Nine Chapters" here happen to be the name of another member of the delegation-atmospheric physicist Zhao Jiuzhang. Hua's wonderful pair made the audience fall for it.

1980, when Hua directed the overall planning method and optimization method in Suzhou, he wrote the following couplets: watching chess is not a gentleman, helping each other in the same boat; Be a person with regrets and correct your mistakes.

3. Chen Jingrun's marriage story

Chen Jingrun is a contemporary mathematician. 1977, Chen Jingrun was admitted to 309 Hospital due to illness, and met Yu Kun who had just been sent to the hospital from Wuhan Military Region for further study.

In the past, Chen Jingrun didn't even touch the edge of a woman's name and didn't even say a word. This time, Chen Jingrun, who is nearly half a century old, saw Yu Kun, his eyes lit up, and he greeted Yu Kun kindly, and he talked too much. Later, Kun was sent to the ward in Chen Jingrun as a doctor on duty.

There are more opportunities for such contact. Every time Kun Yi appears, Chen Jingrun is particularly happy. One day, Chen Jingrun asked Youkun with concern, where does he live? Do you have a boyfriend or family? Yu Kun was unprepared and said bluntly, "No, no, it's still early."

Later, Yu Kun also cared about the China mathematician, and they hit it off and fell in love. Finally, one day, Yu Kun asked the mathematicians around him: "You are a great mathematician, and many people worship you. Why did you choose me? "

Facing the beloved girl, Chen Jingrun flushed with anxiety. He doesn't trust young people. It was a long time before Chen Jingrun said, "I thought about it. You don't agree, I will never get married in my life. "

It is this sentence that makes Yu Kun no longer hesitate. She accepted Chen Jingrun's feelings and supported each other. * * * Go through 16 spring and autumn together.

They got married with the help of the organization. Since then, Chen Jingrun, a mathematician known as "idiot" and "eccentric", has a warm home.

Xu Guangqi is an honest official.

Xu Guangqi was a famous scientist and politician in Ming Dynasty. Chongzhen court official, does history, Wenyuange university, cabinet assistant minister. Mr. Xu Guangqi was an honest official and lived a simple life, which was unimaginable at that time.

The bigger the official in Xu Guangqi, the lower the attitude of dealing with people. On Xu Guangqi's 70th birthday, it is customary for officials, relatives and friends to give gifts.

Xu Guangqi has written to tell his classmates in his hometown that all gifts given to him will not be politely declined. Even the gifts from friends and relatives declined politely. The children and grandchildren in Shanghai know the temper and character of the old man and do the right thing.

5. China popularized the duplex method.

While continuing to study mathematical theory, Hua tried to find a way to combine mathematics with industrial and agricultural practice. After a period of practice, he found that the overall planning method and optimization method in mathematics can be widely used in industrial and agricultural production, which can improve work efficiency and change the face of work management.

Therefore, while giving lectures at the University of Science and Technology, he led students to promote the optimization method and overall planning method in industrial and agricultural practice.

At the beginning of 1964, he wrote to Mao Zedong, expressing his determination to take the road of combining workers and peasants. On March 18 of the same year, Mao Zedong wrote back: "I have read both poems and letters. Top gun, congratulations. "

He wrote "Brief Introduction and Supplement to the Master Planning Law" and "Brief Introduction and Supplement to the Optimal Selection Law", and personally led the teachers and students of China University of Science and Technology to some enterprises and factories to promote and apply the "double methods" to serve industrial and agricultural production. "Go to Jianghan to fight the heat in summer and go to Songliao first frost in winter."

This is a portrayal of his life at that time. In 1965, Mao Zedong wrote to him again, congratulating and encouraging him to "work hard and serve the people, not the individual".