Gradebook calculation formula should support detecting null (ungraded) grades and it should be possible to return null grade for grade item effectively clearing/not setting the grade.
Currently you can't create a formula that leaves course total grade empty when evaluating the formula with some assignments completed. Problem is that gradebook evaluation doesn't know if grade is missing or is actually 0 since null grades are automatically converted to 0 for grade calculation.
Example formula that is not currently possible
- If both assignment and exam have grades with 50 or more points, calculate average of them for final grade (pass).
- If both assignment and exam have grades but at least one of them is less than 50 points (can be 0), set final grade to 0 (fail).
- If either or both assignment or exam grade is missing, do not set or clear final grade (unfinished).