Specification for "grade format changes" and numerical representation of letter grades in a letter grade book

Functional descriptions:
Define specifications that describe in details what grade format changes we allow for a letter grade type gradebook. The current grade formats are:

• Letter Grades with /- (A, A, A-, B+, ...)

• Letter Grades (A, B, C, ...)

• Pass / Not Pass (P, NP, S, ...)

We also need to determine how to document the letter grade to numeric value mappings. Each letter grade has an assigned numerical value, which is used for grade calculation purposes. In terms of grade calculations, gradebook2 handles a letter grade type gradebook the same way as a percentage type gradebook.

Copied from GRBK-800:
Discussion of possible requirements:
1. Investigate having GB2 block submissions from other tools if it's letter grade gradebook
2. Investigate individual tools that do grading; do not show submit to gradebook option for letter gradebooks (this may be a big effort)
3. Consider completely implementing the simple grade mode (A,B,C....) in addition to plus/minus (A+/, B+/....)
4. Short term fix is to hide the option of using simple letter grading (would also include #7)