I am currently taking my first proofs class, and I am finding it a little tougher than other math courses. This problem has me stuck for a proof, even though I find it obvious intuitively
Prop: If such that and then
Well you can say m+n=m+p and then add the additive inverse of m to both sides and continue
The Art of Proof has this exact proof outlined on the home page funny enough, it references another proposition so be sure to click the link in the proof