Choose the down arrow and select Save as New Equation. If you have the Excel desktop application you can use the Open in Excel button to open your workbook to view and insert equations there. After you insert the equation the Equation Tools Design tab opens with symbols and structures that can be added to your equation.
Explains how to input an equation into Excel 2010 using an engineering example.
Choose the down arrow and select Save as New Equation. Also learn how to work with exponents and basic mathematical functions. There are multiple equations in the drop-down list then scroll down and select one of them to meet your actual needs. Now the Pivot Table is ready.