SSRS 2008 - How to Total values from an expression I'm trying to figure out how to total values from a calculated field.

In the example below, I have the following expression:

=IIF(Fields!Role.Value = "Contractor", Fields!actualwork.Value * 100,
Fields!actualwork.Value * 77)


Now I want to provide a total, but it doesn't show up on the report. Is there something I'm missing?
You actually just put a SUM around the outside: 

=Sum(IIF(Fields!Role.Value = "Contractor", Fields!actualwork.Value * 100,
Fields!actualwork.Value * 77))


It will evaluate that row by row and will provide the correct sum.