When you add fields to the body of your Microsoft Excel 2010 PivotTables, Excel gives them a label of "Sum of X" or "Count of X," where X is the name of the field. Excel has to do this for the program to differentiate between the fields, but it can be frustrating if you are trying to customize the look of your table. You can remove the "Sum of" from the PivotTable, but if you try to leave the field name as a column header, Excel will give you an error, so you have to take an extra step to complete the process.
Click on a cell in the PivotTable in the column from which you want to remove "Sum of."
Click the "Options" tab on the toolbar, then click the "Field Settings" button under the "Active Field" area of the toolbar. A small window will pop up.
Place your cursor in the "Custom Name" field and erase the "Sum of" from the name.
Move your cursor to the end of what is left and add a space to the name. This is because once you remove the "Sum of," the remaining name is that same as a recognized field in the field list, and if you try to make a second field, Excel will give you an error. The extra space lets Excel differentiate between the two names, but they will look the same to anyone who views your PivotTable.