You've probably never given a second thought to the dollar bills sitting in your wallet right now. Most people don't. They're just money, right? Something to grab for coffee or parking meters, and ...

Pull any bill out of your wallet. See the dark green numbers on the top-left and top-right corners? Those are serial numbers, and some are more rare than others. If you happen to have paper money with ...

If you need to calculate dates in your spreadsheets, Excel uses its own unique system, which it calls Serial Numbers. Every date (month, day, year) and time (hour, minute, and second) has an ...