Example: Teacher gives an extra credit Homework assignment that is worth 5 points. Sally Student earns all 5 points and has a cumulative grade of 90.

Percentages:

Teacher sets the max points on the extra credit assignment to 100 points

Teacher gives Sally Student a 5 for points on the assignment in the grade book - 5% (.05)

The 5% points are added into the Homework "Assignment Grade" (see first part of formula below).  The Assignment Type Average is then factored into the Cumulative Grade based on the weight of the Homework assignment type (see the second part of the formula below)

For each assignment type:
sum(assignment grade / maximum points * factor) / sum(factor) = assignment type grade
Then:
sum(assignment type grade * weight) / sum(weight) * 100

Total Points:

Teacher sets the max points on the extra credit assignment to 5 points (maximum points the student can receive)

Teacher gives Sally Student a 5 for points on the assignment in the grade book

The 5 points are added into the number of points earned by the student (see "Assignment Grade" in formula below).

sum(assignment grade * factor) / sum(maximum points * factor)

So if Sally Student had earned 90 points out of 100 possible points for her cumulative grade of 90, the extra credit points would be added to the 90 points attempted, bringing it to 95 points earned divided by 100 possible points.

Total Points with Weight:

Teacher sets the max points on the extra credit assignment to 5 points (maximum points the student can receive)

Teacher gives Sally Student a 5 for points on the assignment in the grade book

The 5 points are added into the number of points earned for the Homework Assignment type (see "Assignment Grade" in the formula below).  The new Cumulative is then calculated based on the assignment category weight (see the second part of the formula below).

For each assignment type:
sum(assignment grade * factor) / sum(maximum points * factor) = assignment type grade
Then:
sum(assignment type grade * weight) / sum(weight) * 100