AutoGrade
I like this grading app and ZipGrade, however it would be tremendously helpful to students if you added the following feature.
For paperless grading, after the user selects the number of questions for an exam (variable from 20-200), and then enters the answer key, the user may elect to "Take Test", whereby an empty grading sheet opens on the screen and the user enters the answers. When finished, the user selects "Grade Test", whereby the app will automatically compare the user answers against the "Answer Key", and returns the grade result, indicating what questions were missed.
This app function would help thousands, if not millions of students world-wide.