# Thread: Poofs

1. ## Poofs

Prove that if the sum of two integers is even then either they are both even, or they are both odd.

I just don't understand proofs at all..

2. Originally Posted by TGS
Prove that if the sum of two integers is even then either they are both even, or they are both odd.

I just don't understand proofs at all..
Merely note that $2n+1+2m=2(m+n)+1$.

3. I just don't understand proofs at all..
Yes, you do! Mathematical proofs are just common-sense reasoning with a higher standard of precision. For example, suppose you have two magnets. You put an end of the first magnet to an end of the second one, and they repel. You have to prove that either both ends that you put together are north or both are south. Well, how could it be otherwise? If one were north and the other south, then ...