Explanation

The most common Subtotal calculation is Sum.

Steps

1. Sort the data by the grouping column.
2. Select the data.
3. Go to Data → Subtotal.
4. Choose At each change in:
5. Choose Use function:
6. Select the Sales
7. Click OK.

Example Result

Excel also creates an outline so that detail can be collapsed.

Practice

Create City-wise Sales Subtotals.