Determining a final grade for a student via a gradebook calculation appears to only be possible using mathematical operations. There are some number of instances, not all of which will be possible to list here, where such restriction cannot readily, or even actually at all, allow the teacher to determine a final grade through gradebook (thus requiring other calculations, manually entering or checking data, etc).
Of particular interest, to me at least, are the following prospects:
- Different groups who share a sub-set of assessment items from a course, but who do not share other sub-sets. As per [this discussion|https://moodle.org/mod/forum/discuss.php?d=355362|https://moodle.org/mod/forum/discuss.php?d=355362].] and [this discussion|https://moodle.org/mod/forum/discuss.php?d=335289.]
- Any other situation where it is not practical to exclude empty grades (as a student might miss an assessment completely)
- Achieving a certain result in a non-numeric scale as a qualifying condition for a score to be included.
- Achieving a score in one major assignment can override the scores in some minor assessments, so they wouldn't (as) included (eg. if 78% were scored in the major, then exclude the scores in the minors that were less than 78%).