Ok, suppose my sheet looks like the following:

A B C
Debit Credit Balance
100 100
300 400
50 350

I just typed those values in but I would like to have Column "C" compute
that if the amount is column "A" then add to get the balance in column "C";
and subtract if the amount is in column "B" . I would like for this formula
to be able to go all the way down column C. ANYONE????