1. Open the document you would like to make the changes to in Microsoft Excel.
2. Locate the cell that contains the total and make note of the cell number --- for example, 'E2' or 'F15.'
3. Select the empty cell in which you would like to have the subtracted result shown.
4. Type '=X - Y' where X is the number of the cell containing the total and Y is the number or cell you would to subtract from the total.
5. Press 'Enter' and the cell will now show the subtracted total.