My oldest is very good in math. BUT he hasn't memorized his addtion facts completely, and thus hasn't memorized or easily recall  his subtraction facts. He can borrow, carry, do word problems, perimeter...He can add 189379+120869, but he can't always immediately tell me what 7+8 is. I was trying to come up with something that was a little more independent, and a little less boring that the standard flash cards. Plus something that didn't involve time, writing facts on a sheet of paper, etc....So here is what I made:

It has pockets from 1-20 and sticks for 0-20 both subtraction and additon. It hasn't passes the test yet since we are out of school and he knows it....but I'll give it a try when we get back to books at the beginning of July.