prove that the sum from j=1 to j=n of combinatorial(n, j) is 2^n.

so basicially i have to prove that the sum of the (n+1)th row of pascal's triangle is 2^n. I have tried using induction on n and the definition of combinatiorial(n,j) = n!/[j!(n-j)!] but I keep getting stuck. If someone could provide guidance as to how I should approach this problem it would be more helpful than a straight solution because I am trying to solve problems as practice for an exam