Loving all the resources mentioned here. I want to check out the "Monsters" book! That sounds right up my ds' alley.
We are doing Xtramath for addition/subtraction as part of DS K curriculum. It's very minimalistic. What I think is good, however, is that it truly is a site that pushes MEMORIZATION of facts. Give a short amount of time, ds can work through a lot of problems in his head, but he doesn't have any math facts memorized other than VERY basic.
Can't wait to check out a few more of these sites.
