Creating a subtotal in Excel:
Click on the range of cells that you want to subtotal. Then click on the Data tab to reveal the Data Ribbon options. You will find the Subtotal button in the Outline Group.
A pop up box will appear. Under At Each Change In, select the correct value option that applies to your worksheet. Select the funtion you need for your subtotals under the Use Funtion menu. Then select the column you want the subtotals caculated.
Then Click on OK.
To remove a subtotal. Click on any cell in the subtotaled column. Click on the Data tab and then click on the subtotal button in the Outline group. Finally, click on Remove all.