These are all great ideas, thank you!
aeh - I used piles of books tonight to teach multiplication and it worked! He caught on in about two-three minutes. (Gulp. This is the child I was second guessing assessing later this spring.) He also was able to take the concept in his head to do multiples of ten. (He's been into tens lately.) We did a few division problems with books and he got that, too.

I'll look at education unboxed, puffin. Is it something you'd recommend?