Use Excel 2000 Conditional Sum Wizard to Select and Add Figures 
Do you work with long lists or tables of figures in Excel, and need a
quick way to total just a subset of the numbers? For example, if you
receive figures that include sales of all your company's products across
the country, you might want to total the sales for one region or
product.
Excel provides several ways to create this kind of conditional total,
and one of the easiest to use is the Conditional Sum Wizard. This article
explains how to use the wizard and, to help more experienced users
work with the formulas created by the wizard, it also explains how the
formulas work.
First, Determine What Data You Want to Total
Before using the wizard, review your data and consider what totals you
want to calculate. The Conditional Sum Wizard works with data organized in
a list, where each column has an identifying label and contains related
facts. For more information about organizing your data in list format,
type list guidelines in the Office Assistant or on the Answer
Wizard tab in the Excel Help window, and then click Search.
Here's an example of a list that has three facts about each sales
figure: the month, region, and product sold.
You might decide to calculate a total that's based on one condition,
such as the total sales for a region (South region sales in the above
example). Or you might have more than one condition, such as calculating
the sales for one product during a particular month (November beverage
sales). In a short list like this one, these calculations would be easy to
do manually. The wizard makes it just as easy to perform such calculations
for lists that contain hundreds or thousands of lines of data.