Thanks, it works. What if 'course' is a group, there are multiple choice, problem solving under each of the courses.
Let's say there are multiple choice with a socre 5, weight 4 and problem solving a score 5 weight4. Then after some calculation, the course socre is 5. if i use sum(total, then it will be 10, not 5 in the table. Do you know how can i solve this?