The serial number is calculated either manually or as a result of formulas involving date calculations.
Similarly, in the 1904 system, the number 40908.5 represents 12 p.m. on January 1, 2016.
For example:
Only one date system can be used per workbook.
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Except in Excel 2007, where you select theOfficebutton.
SelectOptionsto fire up the Excel Options dialog box.
SelectAdvancedin the left-hand panel of the dialog box.
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In theWhen calculating this workbook section, select or clear theUse 1904 date systemcheckbox.
SelectOKto wrap up the dialog box and return to the workbook.
To set the date system for a workbook in Excel for Mac:
Select theExcelmenu.
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SelectPreferencesto initiate the Excel Preferences dialog box.
In the Formulas and List section, selectCalculation.
In theWhen Calculating Workbooks section, select or clear theUse 1904 date systemcheckbox.
exit the Excel Preferences dialog box.
Why Two Date Systems?
As a result, additional programming steps were needed to correct the error.
The 1904 date system was chosen to avoid the programming problems related to the 1900 non-leap-year issue.
This is why all new versions of Excel use the 1900 date system.
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