Entering dates and times
Excel treats dates and times as special types of numeric values. Typically, these values are formatted so that they appear as dates or times because humans find it much easier to understand these values if they appear in the correct format.
Excel handles dates by using a serial number system. The earliest date that Excel understands is January 1, 1900. This date has a serial number of 1. January 2, 1900, has a serial number of 2, and so on. This system makes it easy to deal with dates in formulas. For example, you can enter a formula to calculate the number of days between two dates………