Pivot tables

Go to data, then pivot table and chart and follow the wizard. You must have your data already on the sheet first. If for example you have a sheet of sales data and each row has a country to show where the sale happened, you can put it into a pivot table to give a group summary on sales per country. It will show all country data, or you can pick a particular country and it will automatically give you a sum of the sales value or the number of sales depending on the option you set.