1. The problem statement, all variables and given/known data Roll 7 dice. What is the probability that the sum of the numbers is 14? 2. Relevant equations Possibly a probability generating function because the problem comes from the chapter that deals with it but I can't think of which one (if any actually apply). 3. The attempt at a solution Here is the solution: 6-7[(13 choose 7)-49] I really have no idea why. The 67 in the denominator I understand because that is the total number of different ways you can roll 7 dice. Where does the rest come from?