The most difficult math problem is proving Goldbach's conjecture.

Goldbach conjecture can be roughly divided into two kinds (the former is called "strong" or "double Goldbach conjecture" and the latter is called "weak" or "triple Goldbach conjecture"): 1. Every even number not less than 6 can be expressed as the sum of two odd prime numbers; 2. Every odd number not less than 9 can be expressed as the sum of three odd prime numbers. Consider expressing even numbers as the sum of two numbers, each of which is the product of several prime numbers. If the proposition that "every big even number can be expressed as the sum of a number with no more than a prime factor and another number with no more than b prime factor" is recorded as "a+b"1966, Chen Jingrun proved that "any big even number can be expressed as the sum of a prime number and another number with no more than 2", which is far from "/kloc-0".