Testbed

Quick. What's 9 times 7?

Testbed was born out of the frustration of not having a simple, beautiful, easily extensible app to practice answering these sorts of questions. Out of the box, it handles mental maths -- from the easiest to the ost difficult you are likely to run across in daily life -- as well as U.S. Presidents, and that's just the start. Write your own questions in a simple derivative of JavaScript, the language that powers Google's, Amazon's, and Facebook's websites. Edit them on the go with the simple, easy in-app environment or use the fully featured inbuilt desktop development program to work on any PC. Then, package them into QJS files with the included one-click tool to share them with the world, or import, remix, and test yourself on other people's QJS questions. There's no cloud, no fee, and no data usage. Everything is stored securely on your device, so you can keep your work secret or share it with as many people as you want.

If you're a student, Testbed puts you in control of your revision, letting you make the choice about what sort of questions you want to see. If you're a teacher, Testbed lets you share question formats with your class, giving students an inexhaustable collection of test material. If you're a programmer, Testbed will let you hone your JavaScript skills in a safe and portable environment, creating something unique and useful. Testbed has something for everyone, and it's only going to get more powerful as time goes on.

By the way, 9 times 7 is 63.