Math Puzlr: Puzzles & Riddles for iPhone
It is no secret that solving puzzles and riddles are great for your brain. Math Puzlr is an iPhone app that comes with plenty of puzzles to train your brain and help you kill some time. It not only has puzzles for you to solve but also lets you challenge a friend in Local Versus Mode.
This app comes with explanations for every puzzle. It has a hint function when you are stuck. You can download this app for free.