You assign weights (percentages) to grade categories, and an overall grade is calculated for you. This system calculates as follows:
Finds a student's average for a category.
Multiplies each category’s average by its weight (as a decimal), giving category scores.
Adds the category scores for an overall grade out of 100%.
The table shows weighted by category grading. In the Essay category, the student averaged 75. Multiplied by the category weight, .5, this gives 37.5% for Essays. In the Test category, the student averaged 95. Multiplied by the category weight, .5, this gives 47.5% for Tests. Adding the category scores (37.5 + 47.5) gives the student an overall grade of 85%.