One of the most powerful feature of an Excel Table is the use of formulas to calculate its Column contents. To activate this you need to click in your Table and go to the Table Tools tab in the Ribbon. From there you simply need to activate the Total Rows check box.
This will add a Totals Row at the bottom of your Table and by clicking in any of the boxes, a list of formulas will appear! You can use the default formulas like Average, Count, Count Numbers, Max, Min, Sum plus you can click on More Functions which will let you choose any of Excel´s many formulas. Try it out by downloading the workbook below.