How to prove (not show) that 1+1=2
I guess 1+1=2 is a convention.
if a single entity is called 1 (conventionally) then its double will be called 2(conventionally). since two quantities are individually single therfor 1+1=2 must hold. [for this operation of addition is also defined conventionally.]
this question is similar to the question why B comes after A.(even it is a convention)
$\displaystyle x+x=(x+x)=2(x)$
A unit added to a unit is two of the same unit, by definition.
$\displaystyle =$ means "what is before" is the same as "what is after".
If $\displaystyle x=1,$
$\displaystyle 1+1=2(1)=2$
This proof requires the definition that the "symbol" 2 represents two of the same unit,
whatever that unit may be.