I need to be able to determine full retirement age, based on Year of Birth,
from the Social Security tables - I've actually figured out how to get and
accurate YY MM (in custom formatting), by subtracting date of birth from date
of retirement. -

But when I try to use the Year of Birth, by formatting the DOB into YYYY, I
cannot use that figure in other calculations, because it has been converted
to the Excel serial number.

Any thoughts?