283 years ago today, on June 7, 1742 (May 5, 1742), Goldbach's conjecture was proposed. On June 7, 1742, Goldbach's conjecture was proposed. In a letter to Euler in 1742, Goldbach proposed the following conjecture: Any integer greater than 2 can be written as the sum of three prime numbers. Since the convention "1 is also prime" is no longer used in mathematics today, the modern statement of the original conjecture is that any integer greater than 5 can be written as the sum of three prime numbers. Euler also proposed another equivalent version in his reply, that any even number greater than 2 can be written as the sum of two prime numbers. The common conjecture statement today is Euler's version. The proposition "any sufficiently large even number can be expressed as the sum of a number with no more than a prime factors and another number with no more than b prime factors" is written as "a b". In 1966, Chen Jingrun proved that "1 2" holds, that is, "any sufficiently large even number can be expressed as the sum of two prime numbers, or the sum of a prime number and a semi-prime number". This problem was proposed by the German mathematician C. Goldbach (1690-1764) in a letter to the great mathematician Euler on June 7, 1742, so it was called the Goldbach Conjecture. Chen Jingrun: The world's first mathematician to conquer Goldbach's conjecture Goldbach (Goldbach C., 1690.3.18~ 1764.11.20) was a German mathematician; was born in Geonigsberg (now known as Kalinin City); studied at Oxford University in England; originally studied law, because he met the Benuli family during his visits to European countries, he became interested in mathematical research; he worked as a middle school teacher. He came to Russia in 1725 and was elected a member of the Petersburg Academy of Sciences in the same year; he served as the secretary of the Petersburg Academy of Sciences from 1725 to 1740; he moved to Moscow in 1742 and served in the Russian Foreign Ministry. In Xu Chi's reportage that year, the Chinese knew about Chen Jingrun and the Goldbach conjecture. So, what is the Goldbach conjecture? Goldbach's conjecture can be roughly divided into two conjectures: ¡ö 1. Every even number not less than 6 is the sum of two odd primes; ¡ö 2. Every odd number not less than 9 is the sum of three odd primes. Chinese mathematician Chen Jingrun proved in 1966 that any sufficiently large even number is the sum of a prime number and a natural number, and the latter can be expressed as the product of two prime numbers. "Usually this result is expressed as 1 2. This is the best result for this problem at present. One of the greatest conjectures, how many people have worked hard and dedicated their lives to it! We are proud that this conjecture was conquered by Chinese mathematician Chen Jingrun." Advancing the a b "Problem In 1920, Brown of Norway proved" 9 9 ". In 1924, Ratmacher of Germany proved" 7 7 ". In 1932, Estermann of England proved" 6 6 ". In 1937, Lacey of Italy proved" 5 7 "," 4 9 "," 3 15 "and" 2 366 "successively. In 1938, Buchsitab of the Soviet Union proved" 5 5 ". In 1940, Buchsitab of the Soviet Union proved" 4 4 ". In 1956, Wang Yuan of China proved" 3 4 ". Later proved" 3 3 "and" 2 3 ". In 1948, Reni of Hungary proved "1 c", where c is a large natural number. In 1962, Pan Chengdong of China and Barbahn of the Soviet Union proved "1 5", and Wang Yuan of China proved "1 4". In 1965, Buchsitabo and Vinogradov of the Soviet Union, and Bombili of Italy proved "1 3". In 1966, Chen Jingrun of China proved "1 2".