Oh, I can't think of the name right now. Maybe someone else will remember. There are self checking drill sheets, they're about the size of a sheet of paper but heavier and they have problems and you put a piece of notebook paper under and the kid writes the answer in the square and can self check.
I guess I've given you enough info to make you curious, I'm sorry I just can't remember what they're called. Hopefully someone else knows what I'm talking about. :)