# Help creating complex formula using ISNUMBER

#### justinjevans

##### New Member
Hi, I'm trying to create a grade sheet to track my students' progress. I've been searching all over and can't figure this out.

I would like to be able to see each students' grade-in-progress, according to current assignments/exams.

https://1drv.ms/u/s!Ah_05qUKB0mwhpYi00jQOfaKCN906Q

In column S, I am trying to use the following formula:
=IF(ISNUMBER(N30),(N30/N31)*N32,"")+(ISNUMBER(O30),(O30/O31)*O32,"")+(ISNUMBER(P30),(P30/P31)*P32,"")+(ISNUMBER(Q30),(Q30/Q31)*Q32,"")

There are 4 columns used to calculate the final grade: N, O, P, and Q
I want column S to only use those cells which have a grade entered.

Note: Column N is the total of quiz scores listed in columns B through M

#### wwbwb

##### Well-known Member
Try this:

=IF(ISNUMBER(N30),(N30/N31)*N32,0)+IF(ISNUMBER(O30),(O30/O31)*O32,0)+IF(ISNUMBER(P30),(P30/P31)*P32,0)+IF(ISNUMBER(Q30),(Q30/Q31)*Q32,0)

#### justinjevans

##### New Member
That did it! Thank you so much!