For many years, I used the SUBTOTAL function in Microsoft Excel to create easily visible subtotals at the top of my worksheets. However, when I encountered AGGREGATE, this became my go-to function ...

Adding a condition to a simple revenue sheet might spell trouble in Microsoft Excel, but don't worry--a simple conditional function can handle the request.

Click the Data tab. Click Subtotal in the Outline group. In Excel 2003, Subtotals is on the Data menu. In the resulting dialog, choose Count from the Function dropdown.