1. Open EXCEL Help.
2. Find the section on functions.
3. Print the help on the SUM function.
4. Now print the help on the COUNT function.
5. Explain to the chowderhead that even EXCEL doesn't need a SUM all of the time.
6. Immediately leave the room just in case his brain explodes from having too much data in it at one time.
7. As a precaution, the day you are going to do this... wear older clothes in case his brain-burst involves a large splatter factor.