Oooh, I love math! Exactly what level of math are you trying to incorporate? Arithmetic, algebra, calculus? If it's just counting here's a fun game I've done: I blindfolded my boy and told him to keep track of how many whacks he got on either his nipples, ass, or cock, while I interchanged randomly what I'd hit (I kept track by making tallies), and when I was done he had to tell me the number of whacks he got on each respective body part (try keeping track of three separate cumulative counts in your mind; it is very difficult). Then I added up how much he was off by, and he got that many more whacks, but with a more painful instrument . There's a reward if he's ever perfectly spot-on, but that has yet to happen.