When I took discrete math as an adult I realized that this was a subject I would have enjoyed and done well at much earlier in life, even in my early teens.
Does anyone know if there are good books, particularly on combinatorics, aimed at people in middle or high school? I'm thinking particularly of one enthusiastic young programmer of my acquaintance.
(Note: I have moved this question from its original posting on StackOverflow. Before it was removed from there, someone suggested Concrete Mathematics and Bryant's Aspects of Combinatorics, both of which are even harder than the various books by Grimaldi, Epps, Rosen, and Roberts, which I used in college-level courses. Someone else suggested Martin Gardner's books. But actually, I'm looking for something more systematic than math games yet aimed at a less mature reader than a college-level textbook.)