Equation Help

[Guest]

I can't figure out an equation, or if an equation for its even possible. I'm
using Excel 2003

My spreadsheet has multiple columns, but they repeat. A is 'Part number' B
is 'Parts Completed' C is 'Date Completed'.
Then it repeats with C being Part number and so on.

I need an equation that will sum every third column. Basically
=sum(A1+D1+G1) and so on. But is there any way I can make the equation short
so that I don't have to enter in every column? This spreadsheet goes all the
way to column IU or something like that.

 

[T. Valko]

Try this:

=SUMPRODUCT(--(MOD(COLUMN(A1:IU1),3)=1),A1:IU1)

Biff

 

[MartinW]

Hi Sarah,

One way is to insert a blank helper row, row 2 in your example.
In A2 put =A1
In D2 put =A2+D1
Highlight the three cells B2,C2 + D2 (B2 +C2 being blank)
Grab the fill handle and drag across to the end of your sheet.
You will then have a running total of every third column

HTH
Martin