Show different calculations in PivotTable value fields

Tip: You can use this feature to try different calculations in a value field. However, because you can add the same value fields to a PivotTable more than once, you can also use this feature to show the actual value and other calculations, such as a running total calculation, side by side.

https://support.microsoft.com/en-us/office/show-different-calculations-in-pivottable-value-fields-014d2777-baaf-480b-a32b-98431f48bfec