Excel Help

C

Chris

I am having trouble using offset to sum up every third
column, could someone please explain
 
R

Ron Rosenfeld

I am having trouble using offset to sum up every third
column, could someone please explain
Click to expand...

I don't know about using OFFSET, but this formula will:

=SUM(IF(MOD(COLUMN(A1:Z1),3)=0,A1:Z29))

This is an **array** formula so must be entered by holding down <ctrl><shift>
and <enter>.

As written, it will sum c1:c29, f1:f20, i1:i29, etc.

If you want to start at column A, then change the equality to a 1.


--ron
 
R

Ragdyer

Every third column starting from ... where???

A1:X1
A ... D ... G ... etc:
=SUMPRODUCT((MOD(COLUMN(A1:X1)-1,3)=0)*(A1:X1))

A1:X1
B ... E ... H ... etc:
=SUMPRODUCT((MOD(COLUMN(A1:X1)-2,3)=0)*(A1:X1))

A1:X1
C ... F ... I ... etc:
=SUMPRODUCT((MOD(COLUMN(A1:X1),3)=0)*(A1:X1))
 
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