Trouble with budget totals

[Msstaves]

I've got a question on creating a budget in access:

I've got a list of accounts which are of different types. Some are revenues, and some are expenses. How do I make it so that the totals at the bottom are taking the difference between revenues/expenses rather than just adding them all up?

My report looks like this

Revenue
Variable Expense
Direct Expense

Total

Is there any way I can do this other than inputting the expenses with a negative sign?

Thanks

 

[pbaldy]

One way would be something like this as the control source of a textbox in the report footer:

=Sum(IIf(AccountType = "Revenue", AmountField, -AmountField))

Obviously that would rely on some way of identifying each record.