How did Chen Jingrun prove that 1+ 1=2?

Are you talking about Goldbach conjecture? Then, let me tell you that the so-called "1+ 1" or "1+2" is just an abbreviation. Goldbach conjectures that anything greater than

Even number 6 can be expressed as the sum of two prime numbers, usually expressed as "1+ 1". China mathematician Chen Jingrun proved in 1966 that any sufficiently large even number is the sum of a prime number and a natural number, which can be expressed as the product of two prime numbers. Usually this result is expressed as "1+2". This is the best result of this problem at present. Please note that here, "1+ 1" is just a short name, not one plus one in the arithmetic sense. I'm afraid I won't write down Chen Jingrun's proof process here. Even if it is written here, how many people can understand it?

If you mean "1+ 1" in the arithmetic sense, that is, how to prove that one plus one equals two, then I tell you, there is no need to prove it. One plus one equals two is the main postulate of mathematical axiom system. In other words, it is a postulate that one plus one equals two, which is self-evident and the premise of other mathematical theorems. So there is no question of how to prove that one plus one equals two.

In addition, I would like to remind you that what Chen Jingrun proved is not "1+ 1=2". This is common sense, don't joke.