My 10-year-daughter Jane and I love Yodel-Oh!, an iOS target tapper game where you have to keep a Swiss mountain climber from falling off the edge of a cliff. The developer, Spinlight, just announced a spin-off, called Yodel-Oh! Math Mountain (iPad, iPhone) that adds the challenge of having to solve arithmetic problems.
The game is gorgeous, and one of the best things about it is that is free of the annoying crap that many iOS games are larded with: 3rd party add-ons, social network links, location tracking, and in-app purchases. Thanks, Spinlight!