Practical guide and verification
Start from the grading formula
The required final-exam score depends on the current course grade, the final’s weight and the desired overall grade. Make sure all percentages refer to the same grading scale before solving for the unknown exam score.
Impossible targets are useful information
A required score above the maximum possible exam grade means the target cannot be reached under the stated weights. A negative required score means the target is already secured even with a zero on the final, assuming no other grade changes.
Common mistake
Do not treat a category average as the same thing as its course-weight contribution. Convert each weighted component into course points before combining it with the final.