1. The problem statement, all variables and given/known data Prove that for any two integers a and b, a+b=b+a. You may use the face that this holds for natural numbers. 2. Relevant equations 3. The attempt at a solution a=(x,y), b=(u,v) x,y,u,v are natural numbers a+b = (x,y)+(u,v) = (u,v)+ (x,y) = b+a I'm not sure if my attempt was correct.