Microsoft Excel's Month and Weekday functions output numeric values for a given date. The Month function results in the month numbers, such as "3" for March or "12" for December.

Save this for the spreadsheet jocks in your office—we'd bet even the experts don't know all of these formula tips.

Adding a running total to a simple Microsoft Excel revenue sheet isn't difficult, but adding a conditional running total will require a bit more effort. Solutions are simpler than you might think.