please I need your help

I need function that gives grades for example :
A student who got 8 / 6,1 / 8 / 7 / -
the - means that the student misses the exam but has a valid excuse, so this exam will not be count, also we should take care of that each exam has weightening factor.
C14 = 8
D14 = 6,1
E14 = 8
F14 = 7
G14 = -

the weightening factors
C15 = 1
D15 = 2
E15 = 1
F15 = 2
G15 = 1

Thankssss

also the function has to make it able for us that if we add a new row it counts this row too.

First, the simple case that you gave:

=SUMPRODUCT(C14:G14,C15:G15)/SUMPRODUCT(--ISNUMBER(C14:G14))

Now, you also asked that this will work if another row is added. Do you mean another column?

Assuming you do mean "another column", here is the formula for that:

=SUMPRODUCT(OFFSET(C14,0,0,1,COUNTA(C14:AZ14)),OFFSET(C15,0,0,1,COUNTA(C15:AZ15)))/SUMPRODUCT(--ISNUMBER(OFFSET(C14,0,0,1,COUNTA(C14:AZ14))))

Originally Posted by MSP77079

Assuming you do mean "another column", here is the formula for that:

=SUMPRODUCT(OFFSET(C14,0,0,1,COUNTA(C14:AZ14)),OFFSET(C15,0,0,1,COUNTA(C15:AZ15)))/SUMPRODUCT(--ISNUMBER(OFFSET(C14,0,0,1,COUNTA(C14:AZ14))))

Thanks For your answer, yeah i meant a column, you are right! the problem now is that when i enter this function in Excel, it tells me "The formula you typed contains an error". what could be the problem?

I just copied and pasted it back into my workbook. No error.

So ... I am guessing that the problem is we have different (language) versions of Excel. Try replacing commas (,) with semi-colons (.

It may also be that SUMPRODUCT is a function only available with an Excel Add-In Tool Pack (i.e. Analysis ToolPak). I think that would cause that error as well.