First off, thank you all for your assistance with this question.

I am making a database and in a cell I am using the validation list option
for the following selections:
SAT, UNSAT, N/A

My question is this, if the user selects N/A is there anyway for a set of
cells to blank out, so they are not part of another calculation?
example:
cells: M1 N1 O1 P1 Q1 R1
SAT 4 4 2 2.00 100%
N/A - - 2 - -

I would like the N/A option from the list to blank out cells so when we
calculate percentages the N/A catergories will not affect the overall totals.