Eek - feeling a bit stupid here - maths never being my strong point! OK I've
changed the format and as you say all the 2004 dates default to 2004. How do
I get the whole column to subtract the contents of each cell by 365?
Extremely grateful if you can help...
--
lucy


"John Michl" wrote:

To determine the year of the date, change the format (Format | Cells |
Number ) to one of the formats that shows the date. If you created the
dates this year, they would have defaulted to 2005. Since dates are
really just serial numbers, you can do simple math with them like
subtracting 365 to get the same date as last year. If you expect a
leap year to cause problems, you can use some of the Date functions to
extract the month and day from the serial number and combine it with
the appropriate year.

Hope that helps. Let me know if you need more details.

- John Michl