I have two fields - Gross Revenue and Net Revenue from two different data sources. I've combined the data sources in Tableau, and put both Gross Revenue and Net Revenue on the report. However, I would like to create a new column that shows this formula : Gross Revenue - Net Revenue, so I can see the difference. How do I do that? I'm sure it's pretty easy. I believe it's create new calculation, but it's not calculating correctly in the new column.