The subtotal dialog box will appear. In box allows you to determine where calculations will be made. Select the calculation to be made in the Use Function box, and determine which columns are subtotalled in the Add Subtotal to box. The check boxes can be used to control where Excel places new subtotal information. When using the subtotals command, always be sure to have headings for your columns.
Headings can come in many forms.
As long as they have a format different from that of the columns, and are at the top of the column, Excel will recognize that they represent headings.