A free app for Android, by 5daysweekend.

Mental Math Master is an arithmetic puzzle game, designed to challenge your brain and improve your calculation and mathematical skills. It is a fun way to train your mind and gain new skills, as you have to use your mind to solve complex arithmetic puzzles.

You will be presented with a series of arithmetic puzzles, each one harder than the previous one. Every time you get the correct answer, you will get a point.

One of the challenges here is to reach 10 points within the time provided.