Gradebook

Can someone give me some advice on how to calculate grades for the following:

Chapter grades are made up from the average 5 sets of exercises and a quiz. The grading period grade (9 weeks) is 2/3 the of the chapter average and 1/3 of employability skills. The semester grade is 80% of the average of the 2 grading periods, and 20% of the semester exam.

I'd like to have calculated chapter grades, calculated 9 weeks grades, and calculated semester grades. I can do this with a spreadsheet but I'd rather have the data available to the student in Moodle.

Any and all info will be appreciated.