Hey so I worked on this, if anyone's got any questions about it I'm happy to answer them.
Edit: The FAQ suggests introducing the product and some nifty features, so I might as well.
The main feature that sets Quick Math apart from any other math practice apps is handwriting, you handwrite your answers straight on to the screen. Personally I love this feature, but I've also talked to parents who say it really helped their kids. First off it makes the experience much more transferrable, you're used to answering these math problems with handwriting. Secondly it helps reinforce handwriting skills, especially for kids who are writing numbers backwards (a common problem). It's also a great input method that doesn't take up any screen space creating a very clean design.
The other big feature for us is the way we encourage progress. We used to have a system that rated you on performance, but we know now that research indicates we should be encouraging effort instead. So in our latest version, as you answer more and more questions you head towards unlocking fun new avatars. That means that students who are really struggling are encouraged to practice just as much as those who find it easy. Then, when they're ready, they can choose to try something a little harder.
Theres a bunch of other educational research hidden in there: our difficulties are based around curriculums like Common Core and the Australian National Curriculum, choosing your own activity is a great way to encourage intrinsic motivation and seeing your own times improve helps reframe learning as a process of growth.
PS: It's also great to practice mental arithmetic as an adult 😄
Runno