I want my son to be quick with basic addition and subtraction through the number 12. When I was in school we used to have timed tests and the winner got a special treat. It sure motivated everyone to do better... I would like to do that with my little guy too!
Anything like this I find khan academy really good or just google the problem and you can generally find it on youtube. Or try your library they are really quite good or a bookstore, you might be surprised.