OpenOffice.org 2, Firefox, and Thunderbird for Windows All in One [Electronic resources] نسخه متنی

1.

Enter This Moment

Type =Now() in a cell. When you press

Enter , Calc converts the function to the computer's currently set date and time. You may have to widen the column in which you're working to see the result. You can use this to calculate values based on this moment, such as the number of days old you are.

TIP

Remember that Now() and the other date functions operate as number of days since January 1, 1900. Therefore, when you add or subtract dates with or without using Calc's date functions, the result is always a number of days.

2.

Determine How Many Days Old You Are

Enter your birth date. Type the date in any format. Although you can format the date using the

Format menu, don't worry about the format now; concentrate on what occurs when you use date arithmetic.

Subtract your birth date from the current date to determine how many days old you are. Digits to the right of the decimal indicate partial days since midnight of your birth date.

3.

Determine How Many Weeks Old You Are

Because the dates work in days, you can divide your age in days by seven to determine approximately how old you are in weeks.

4.

Add to Get a Future Date

What will be the date one month from today? Sure, it's simple to look at a calendar, but when you write general-purpose spreadsheets, you've got to be able to apply such formulas to dates to age accounts receivables and other calculations.

By adding

30, 60 , and

90 to today's date, you can display the date when future payments will come due. Calc understands how many days different months have in them, so adding

60 to April 12th properly returns June 11th and not June 12th.

NOTE

Generally, you'll use date formats to hide the time when you work with date arithmetic. When working with time values, a day has 24 hours in it, so you'll need to multiply by 24 to obtain the number of hours represented by the value. When you subtract two date and time values, if you multiply by 24 you'll get the number of hours represented. For example, if you subtract a cell containing your birth date from a cell containing today's date, then multiply the result by 24, you'll learn how old you are in hours.

5.

Use Other Date and Time Functions

Several date and time functions are available to make working with dates and times simpler. Today() returns the date only (without the time, unlike Now()). Day() returns today's day of the month of whatever date you use as its argument. Weeknum() returns the week number (within the year, from 1 to 52) of the date inside its argument list. Weeknum() requires two arguments: a date and either 1 or 2 to indicate that the start of the week is Sunday or Monday, respectively. Month() returns the month number of its date argument. Year() returns the year of the date given as its argument. You'll use these functions to pick off what you want to work with in another formula or label: either the day, month, or year by itself instead of working with the complete date.