sum of 2 Months basis

[Andri]

Dear All,
Please help as follows:
A B C
Row1 288 -
Row2 288 288
Row3 279 279
Row4 288 288 -
Row5 279 279 279
Row6 288 288 288

I would like to sum every column A,B and C with two month basis (Where
Column A, starting sum the number from row1, while column C, starting sum the
number from row5).

Purpose, i want to know with ROW() function, then +2 for range then sum
those two number.
Or please help any better solution.

TIA...

 

[Debra Dalgleish]

How do you distinguish the months? If you give an example of what you're
trying to do, and the result you expect, someone may be able to help.