Was wondering if anyone could help with this question i've been struggling with. Im sure I'm just missing something simple but can't work it out. I need to prove by induction that the sum from j=o to n of j Choose k is equal to n+1 Choose k+1. Think I need to use the identity n Choose k+1 is equal to (n-1 Choose k) plus (n-1 choose k+1). Any help very appreciated!!