As early as 2000 years ago, the working people in China took mu as the unit of land area. An acre is about 667 square meters.

Arabic numerals In the 3rd century, Indians invented a special number. Later, this Indian number spread to Arabia. /kloc-In the 20th century, Arab businessmen brought Indian numerals to Europe, and Europeans called them "Arabic numerals". This is the current Arabic numeral.

China's national standard "Quantity and Measurement" stipulates that when writing multiple digits, every three digits can be divided into one section, and half digits can be left between sections. For example,123.456 million writing:123.456 million.

Postal code consists of six digits: the first two digits represent provinces (cities, autonomous regions); The first three digits indicate the postal area; The first four digits represent counties (cities); The last two digits indicate the office. The factor of perfect number 6 is 1.2.3.6, and the relationship between these factors is: 1+2+3=6. Numbers like 6 are called perfect numbers (also called perfect numbers).

Goldbach conjectures that any even number greater than 2 can be expressed as the sum of two prime numbers. This problem was first put forward by the German mathematician Goldbach, so it is called Goldbach conjecture. This conjecture has not been confirmed so far. People compare this conjecture to "the jewel in the crown of mathematics", and Chen Jingrun has made remarkable achievements in this field.

Geometry and Euclidean geometry are an important branch of mathematics, which mainly studies the related problems of spatial graphics. Euclid, an ancient Greek mathematician, wrote Elements of Geometry, which had a far-reaching influence on the history of mathematical development. This book was introduced to China from/kloc-0 at the beginning of the 7th century.

Golden ratio a:b=0.6 18: 1 About 2000 years ago, there was a saying in China's ancient mathematical work "Zhou Pai Shu Jing" that the circumference of a circle was about three times its diameter.