Example:  

A CSC 102 student scores 100 on every test and the final exam.  Also, the student completes four of eleven programs that are scored 100 each.  The student receives a zero for the remaining seven assignments.  With perfect scores on quizzes and in-class work, the student has an average of 41.6% on the Assignments component and 100% on the Examinations component.

0.8 * 100 = 80 points
0.2 * 41.6 = 8.3 points

Total: 88.3 points for the course (normally a B+ average).

Student's reported grade is a C, because five programs were not completed.