Nine Chapters of Arithmetic is a monograph of China's ancient mathematics, and it is the most important of the ten arithmetic classics. It inherited the development of mathematics in the pre-Qin period and was edited and deleted by many scholars after entering the Han Dynasty. The book was written in the early years of the Eastern Han Dynasty (the first century A.D.), which was the result of the concerted efforts of several generations of Qi Xin. Its appearance marks the formation of China's ancient mathematical system. Later generations are all ancient mathematicians. Many people have commented on it, the most famous of which are Liu Hui (AD 263), Li (AD 656) and others. Nine Chapters Arithmetic contains 246 math problems, which are divided into nine chapters. Their main contents are as follows: Chapter 1 "Square field": calculation of field area; Chapter two "millet": conversion of grain proportion; Chapter 3 "Decline": the problem of proportional distribution; Chapter 4 "Less but Wide": Given the area and volume, find its side length, diameter length, etc. Chapter 5 "commercial engineering": geotechnical engineering and volume calculation; Chapter VI "lose-lose": reasonable allocation of tax revenue; Chapter seven "surplus and deficiency": the problem of dual management; Chapter 8 "Equation": the problem of linear equations; Chapter 9 "Pythagorean Theorem" is used to solve various problems. In Chapter 9, there are many mathematical achievements in arithmetic: (1), and the main achievements in arithmetic are fractional operation, proportional problem and "profit and loss" algorithm. Chapter 9 Arithmetic is the earliest book in the world that systematically describes fractional operation. There are many proportional problems in chapters 2, 3 and 6. It is also relatively early in the world. The "residual" algorithm needs to give two assumptions, which is a creation. In medieval Europe, it was called "double solution". Some people think it came from China through the Arab countries in the Middle Ages. (2) In geometry, it is mainly the calculation of area and volume. (3) In algebra, there are mainly solutions of linear equations, square roots, square roots and general quadratic equations. The chapter "Equation" also introduces negative numbers and their addition and subtraction algorithms for the first time in the history of world mathematics. As a world-famous scientific work, Nine Chapters Arithmetic was introduced to Korea and Japan during the Sui and Tang Dynasties. Now it has been translated into Japanese, Russian, German, English, French and other languages. Chapter 9 Arithmetic * They are: Tian Fang, Li Mi, Descending, Shao Guang, Working, Equal Loss, Insufficient Profit, Equation and Pythagorean. Nine Chapters Arithmetic is the earliest book in the world that systematically describes fractional operation. Among them, the residual algorithm is an amazing creation; The chapter "Equation" also expounds the negative number and its addition and subtraction algorithm for the first time in the history of world mathematics.