1. The problem statement, all variables and given/known data Counting problems are a very tough subject to me, so if someone could give me tips, examples explaining what's really happening, that would be great. 2. Relevant equations I know what permutations, variations, combinations, ... are. The problems involving only one of those are do-able, but those that combine more than one are the difficult ones for me. 3. The attempt at a solution I do not really have a certain problem as I find most exercises rather difficult. Thanks in advance.