It includes a simple calculator with essential functions and educational games to enhanceyour mental arithmetic.You must have been often embarrassed by miscalculating your changes and failingto multiply or divide correctly. Also, you must have been ruined your math tests eventhough you perfectly knew about formulas, just because you made small mistakes. If youunderstand the principles of adding and multiplying, you can calculate everything in yourhead regardless of how long numbers are. Mental arithmetic comes from experience. It