I am trying to figure out how to calculate a sum reducing by a specific amount...i.e. I have 100 lots to pay HOA dues on @ $120 per quarter. I am budgeting to sell 3 homes per quarter so want to reduce this amount by 3 each time and figure out what my final number will be when all 100 lots are sold. Is there a way to do this? I am thinking an amortization schedule but I can get it to work. I can't do a nested if function because there are too many conditions. Any ideas??