If you use Excel 40 hours a week (and those are the weeks you are on vacation), welcome to the MrExcel channel. Home to 2,400 free Excel tutorials. Bill "MrExcel" Jelen is the author of 67 books about ...

Corin Cesaric is a Flex Editor at CNET. She received her bachelor's degree in journalism from the University of Missouri-Columbia. Before joining CNET, she covered crime at People Magazine and ...