[kaj_sotala]

DragonBox ( http://www.dragonboxapp.com/ ) is fantastic. I have literally seen elementary school kids argue over who gets to be the next one to solve equations playing it.

If you have an iOS or Android tablet, they also have a new game called DragonBox Elements up that teaches geometry. After playing it for a while, I'd see triangles everywhere.

If DragonBox gets them hooked on algebra, another fun algebra game is Algeburst (currently only available for iOS platforms AFAIK), which employs a basic get-three-of-the-same-color-in-a-row mechanic, but requiring you to interpret simple algebraic expressions in order to figure out which tiles are of which color. E.g. if there's a tile called 3X + 2X, you can recognize it as being a 5X tile and give it whatever color 5X tiles happen to have on that particular level. (I was only going to try this game to see whether it was any good, but then ended up losing several hours to it.) They also have a "topics in arithmetic" version which doesn't have algebra but rather focuses on basic arithmetic.

10 might be getting a little old for it, and it teaches the basics of programming not math, but in general I would also recommend the Robot Turtles board game. On the topic of games teaching programming, I've also heard good things about the CodeSpells computer game, in which you're exploring a world and can cast spells by writing Java code, but I haven't tried it myself.