I have a simple spreadsheet for calculating students' grades.

Each class, assignment, or test has a point value (not a percentage).

Example:
A class is worth 20 points
A project spread out over a term may be worth 250 points
A test may be worth 50 points.

At the end of the term I calculate grade percentages based on total points
earned for each category.

10 classes x 20 points = 200 total points
Dividing points earned by (10%) of total point values gives me a percentage.
200 points earned = 100%
160 points earned = 80 %
100 points earned = 50%

Project: 250 points
250 points earned = 100%
200 points earned = 80 %
125 points earned = 50%

Test: 50 points
50 points earned = 100%
40 points earned = 80%
25 points earned = 50%

Now I use MAX to find the highest value in 'COL A'. Then, in 'COL B', I
divide all the numbers in 'COL A' by 10% of the highest value to get a
percentage. (EX: 200 points divided by 20 = 100%, 160 points divided by 20 =
80%)

This is a two step process: Find MAX in 'COL A'. Then in 'COL B' adjust the
formula; =QUOTIENT - Numerator 'COL A' Denominator 10% of MAX value from
'COL A'

How can I write a formula to combine these two functions? I.e., formula in
'COL B' finds MAX in 'COL A' and divides all numbers by 10% of MAX value.

I can't set a static number as the denominator because the total point value
varies according to when the grades are calculated. So, what I usually do is
change the denominator in 'COL B' manually.