If possible find a copy of MATHEMATICS OF CHOICE: How to Count Without Counting by Ivan Niven.
It is a publication of the MAA, part of the New Mathematical Library series.
It is full of the sort of topics that I think you are looking to find.
Can anyone please tell me how to teach permutation and combination in a constructive way without giving them the formulas at the beginning of the lesson? How to make sure that students discover the relationships and solve problems without the teacher going into so mch details. This usually bores them. Any activites, suggestions? Thanks.