Most numbers used in business are based on 10 – commonly known as the decimal system. One dollar is $1.00 and a half-dollar is $0.50. Time, of course, is an exception because it's based on 12. The day ...

Excel considers dates and times as numbers in cells, making calculation difficult. Excel processes 6 AM as "0.25," because it is one quarter of the way through the day. If you need to add a number of ...