Book excerpt: Make Excel do the math and make sense of your data Use the Insert Function dialog box, array formulas and functions, and more Excel 2007 has more than 500 built-in functions. This book looks at the top 150, so you can find out which ones will make your life easier. Want to compare a 15-year mortgage to a 30-year mortgage? Forecast expenses for your college freshman? See how your online business is doing? Here's the fun and easy way! Discover how to * Create worksheets to track costs and revenue * Tell the difference among average, median, and mode * Work with statistical functions * Develop forecasts and track trends * Manipulate strings and work with database functions