Matthew Good is the creator of DragonBox+, "an educational puzzle game that also secretly teaches you how to do algebra."
The basic premise is that you must isolate the dragon on one side of the board in order for him to emerge. After each level the dragon will grow a little until he is finally full grown. The game gradually introduces new abilities that mimic algebraic concepts such as elimination, fractions, isolating variables and others without it being obvious.
We were recently at GDC to accept the award for Best Serious Game at the International Mobile Gaming Awards.
We have also seen parents post videos of their children playing the game. For example, a four year old boy solves the equation "e/e + x + (-1) = d" in this video.