To play the role of devil's advocate, I can see what this assignment is trying to do. It's trying to teach that numbers (particularly discrete ones) are representations of a quantity, not just abstract symbols that follow some arbitrary set of rules. I wouldn't be suprised if the kids who successfully learned this way would have an advantage over the rote memorization kids if you were to stick them in a Discrete class 12 years later. As soon as I saw the grids, my mind was screaming "pigeonhole principle!" But that might just be because I have a combinatorics exam in 6 hours.