Last year, I reviewed an amazing app called DragonBox Algebra 5+. It uses a fun gaming approach to secretly teach algebra. I was impressed by how the app is able to cover so many algebra topics in just a few hours.
Recently, the developer released an app called DragonBox Elements, which secretly teaches geometry to kids ages eight and up through gaming. In addition to teaching them about the basic of geometry, it lets them construct Euclidian geometrical proofs by solving more than 110 puzzles.