Grades

do you mean something like this:

=IF(ISBLANK(C2),FORMULA WITHOUT TEST,FORMULA WITH TEST)

where C2 is the cell that holds the test score. If that cell is blank, the formula for scoring without the test is used, else the formula with the test is used.

Is this what you are looking for?

Originally Posted by Michael L

Hello,
I am an Excel newbie, and for some reason my wife has prevailed on me to help her build a spreadsheet for her middle shool grades. Here is the problem: She wants to calculated weighted averages, which is easy enough (in her system, homework is 25%, quizzes 35%, and 1 test at 40%). The problem is that she wants the spreadsheet to recalculate automatically if a test is left blank. Since there is only one test, excel will need to re-weight the averages. So far, I have been doing it manually for the kids who miss a test, but I want to use the IF (ISBLANK) syntax to automate everything. Can anyone help me?
Thanks,
Mike

I will ASSUME that when the test is left blank and there is a recalculation to be done, the percentage weights will be modified as follows:

For homeworks : 25/(25+35) = 42%

For quizzes : 35/(25+35) = 58%

Therefore, your formula is

=if(C2="",0.42*A2+0.58*B2,0.25*A2+0.35*B2+0.40*C2)

where

A2 = homework grades
B2 = quizzes grades
C2 = test grade

Hope is this what you are looking for.

Regards.