FREE today – Mystery Math Museum, a fun & educational app. Kids help a friendly ghost rescue fireflies hidden in the museum. Along the way, they use their math skills to unlock doors rooms and passages. The app permits multiple players with the ability to customize math skills for each player. Kids practice addition, subtraction, multiplication, and division by building equations. This app has lots of “kid appeal” – bonus challenges, fun rewards, not to mention its very cool interface. Highly recommended!!