Adding/subtracting numbers, from a number in a pivot table

[rgillson3]

Is there a way to add/subtract numbers in a pivot table to those outside of the table and copy the formulas down the column?

Whenever I try, the formula "sticks" to the original cell in the table.

For instance, I'd like to subtract multiple rows of Column "X", which it outside the PivotTable, from Column "U", which is inside the PivotTable.