Not sure what you might be after, but if you want them to do math for fun, there's "Sideways Arithmetic from Wayside School" -- Reading is easy, but if I recall correctly, the main character has just transferred to the school and is trying to grok the weird math they have, where the problems are things like EGGS + MAYO = SALAD and DOGS + CATS = FIGHT. So, for the second equation, S must be 1/2 T(and T must be even), and D + C must equal something that carries into the next column... Just pull the answers out of the back. ;)

So have they given us the option to disable their "awesome bar" yet?