New to Microsoft Excel? Looking for a tip? How about a tip so mind-blowingly useful as to qualify as a magic trick? You're in luck. In this MS Excel tutorial from ExcelIsFun, the 598th installment in their series of digital spreadsheet magic tricks, you'll learn how to create a formula to calculate hours worked given an in time, an out time and an in and out time for the lunch break. Learn about how time in Excel is the proportion of one 24 hour day.