1. The problem statement, all variables and given/known data Discover what the rule is and prove it. (Picture attached) 2. Relevant equations Everything is allowed 3. The attempt at a solution This is a problem from a little book of fun math problems i own. I discovered three rules. Given the number of a row you want to study ( marked N ) the following rules tell you: N(N-2)+2 = which number starts the process 2N-1 = how many elements does it have (N-1)^3+N^3 = sum of all numbers in that row. My question is: how am i going to prove this? Do i need to prove all three rules?