MathsQuiz Calculator is an Android Apps that can acts as a calculator, and also can gives random arithmetic question to train your brain.
The feature of the apps is that it looks a calculator, so you can train your mental calculation as if you can using a calculator for work or for doing homework.
You can set the levels that suits your ability of mental calculation. You can set the no, of question, time limit of each question, type of question and the difficulty of each question.
MathsQuiz Calculator can be downloaded in the following link: