Thread: formula:sum

i'm using the sum function as part of a formula. in one cell i have sum(b1:b2). i want to be able to pull the formula over to get sum(b1:b3) in the next cell and sum(b1:b4) in the next, and so on...but, what i get is sum(b2:b3), sum(b3:b4), etc...
any ideas on how to get it to do what i want so i don't have to type the fomula by hand each time?
note: i'm using the sum function as part of a much larger function. everything else in the function behaves exactly how i want.
thanks!!