Autofilling with both column and row counting up

[Robert78]

I hope my title made sense or else maybe this can illustrate what i want to do:

SUM(A101:A199) should in the cell below be SUM(B102:B200) and below that SUM(C103:C201)

How can I do that without needing to type it by hand cause i need to go from column A to IF

[Mark@Work]

Something like this should do the trick:

=SUM(OFFSET($A$101,ROW()-101,ROW()-101,98))

This assumes that your first entry is on Row 101,
alter 101 to whatever row your first entry is on (so the first offset is zero).

It also assumes that you are wanting to sum 98 values.

Mark.