I would like to find out what each entry date would be if I had a
global start date, each entry had a day count and the result would be a
backwards calendar count

Example:

If my global date was May, 30, 2006 (05/30/2006)

I had an entry which the day count was 42

The answer for that entry would be the date (MM/DD/YYYY) 42 days before
the global date

Thanks