Speaking of the question "What does 1+1 equal?"
A lot of people, as soon as they think of the answer 2,
might also have another word pop into their mind:
Goldbach Conjecture.
In many people's understanding, 1+1=2 and the Goldbach Conjecture are basically the same thing.
But in reality...
This is also a huge, widespread misconception.
1+1=2 is an axiom—it doesn't need to be proven.
Goldbach's Conjecture isn't about proving that 1+1 equals the number 2, nothing that simple.
The true meaning of Goldbach's Conjecture is:
Any even number greater than 2 (written with 2) can be expressed as the sum of two primes (written with 1).
For example, 12 = 7 + 5.
Back then, when people said Chen Jingrun proved 1 + 2, they meant he proved that a sufficiently large even number could be written as the sum of either two primes.
Or as a prime (written with 1) plus the product of two primes (written with 2).
For example, 100 = 23 + 7×11.
