Chris said:
When copying birth dates in the format of month/day/year into another
worksheet, somehow the numbers are increased by several digits. Is this a
glitch in Excel for Mac, or is this something that can be fixed?
XL has two date systems - the Mac default 1904 date system, and the
Windows default 1900 date system. They differ by 4 years and 1 day (the
1 day due to incorrectly including the non-existent 29 February 1900 in
the Win system).
Dates are actually just integer offsets from the date system base, so if
you copy a date from the 1900 system and paste it to the 1904 system,
the offset will increase the displayed date by 4 years and a day.
Before copying and pasting, make sure both workbooks are using the same
date system, by choosing Preferences/Calculation and checking or
unchecking the 1904 date system checkbox. It doesn't matter which, as
long as the two workbooks are consistent.
