Why does 1 plus 1 equal 2?

Answer 1

We assign the symbol "1", pronounced by the word sound "wun", to a single entity, for purpose of letting all know that whatever that entity is, it is a single entity.

If then another entity appears, by any means, and we wish to describe that there is now an additional single entity, we assign the symbol "2", pronounced by the word sound "too".

Note that the entities may each be the same, as in "2" apples. Or the entities may be different, say an apple and orange, but we simply wish to describe how many entities of any type are there.

Whenever we place a single entity next to another single entity, we call the combined entities "2", and know that there are thus that many entities there, regardless as to any other characteristics they may have.

We then decided that if we had "2" entities, and added another single entity, still called "1", that we'd call the end result three. And so on.

Thus 1 plus 1 equals 2 because "1" stands for a single entity, and when we add it to another single entity, we've agreed to label that "2".