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 722nd installment in their series of digital spreadsheet magic tricks, you'll learn how to calculate gross pay for the week from time values using the SUMPRODUCT function. Also see what to do if you get a #VALUE! error from blanks in cell using the IF function and an array logical test.