Dr Richard Lissaman from the Mathematics Institute at University of Warwick, UK, recently contacted me about his puzzle app game called Sumaze!
The object is to start with the blue number on top - Your Man - and get to the exit. Along the way, you will change your value in order to pick up keys and get to the exit. Essentially, Sumaze! tests your knowledge of Order of Operations, which is normally a pre-algebra concept.
However, things can get pretty complicated. The game starts with easy stuff and gets to Logs, exponents, square roots and I'm not sure what. (I haven't gotten to Fermat's Room yet.) Still, even in the easier rooms, there are a couple of challenging problems.
Sumaze! is one of those games that has some good puzzles, but will not be very successful. (The App Store has scores of those! One of my favorite puzzles made only $10.)
My recommendation is to overhaul the mechanics to resemble Qwhizzle. That game is similar: but is very successful because of its sparkling graphics, the element of time and the opportunity to compete against others.