It is proven that "Mental Calculation" can be exercised to achieve higher accuracy and performance. Math Brain Free is a mental workout application that tests and exercises your skills in solving simple arithmetical calculations. You face a calculation with 3 possible solutions, solve and find the right answer in 10 seconds. Points and grade depend on time taken and mistakes done.
There are tree difficulty levels in the game:
-Easy: Primary school level -Normal: Average skill level -Difficult: Advanced skill level
For further information, methods and techniques read the Wikipedia entry on "Mental Calculation".
For questions, suggestions and bug reports visit the developers website.