Any number times one equals itself, and any number multiplied by two equals itself plus itself, so 1*2=2 and 1*2=1+1. The transitive property of equality states that if x=y and y=z then x=z. Since both 1+1 and 2 are equal to 1*2, they must be equal to each other, so 1+1=2.
The answer is 2