Mental Arithmetic 1.21
the author of this app says:
Mental Arithmetic is actually an intelligent mental-arithmetic coach.
Here is a program that finds your weaknesses in arithmetic and helps you learn to "syfer" in your head.
Using techniques from current teaching research, this application is aimed at adults. You can even check your overall score and your relative improvement for doing calculations in your head.
The program now has sound, more question categories, a clearer screen and an improved user interface.