Which auto-numbering technique is best (easiest) to use for monthly calendars?

I'm referring to monthly calendars in 'table' format -- i.e., 7 columns
(each column representing a 'day of the week') and 4 or 5 rows (each row
representing a 7-day 'week').

I want to use auto-numbering so that the calendars can be easily changed
(e.g., by adding/dropping a day and seeing the remaining numbers
automatically increment/decrement).

(If the answer may be version-dependent, I'm as far as WORD 2003.)

Thanks.