I have a large database in Appleworks and I need to "weed out" the duplicate records before I print mailing labels. How do I create a "match records" formula to find all records that have duplicate phone numbers in field7, which is the phone number field?

I don't think you can, since you will not be able to provide the actual phone numbers for the match.  What you CAN do, even though it may still take some time, as you have a large database, is to do a SORT your records by phone number.  Then just scroll through the list and delete or edit the duplicate records as needed.  The next thing will be to prevent this from happening in the future.  If your database is REALLY large, you should probably do a "find" request (shift-command-F in Layout menu) for each phone number before you enter it. That should save you from entering the duplicates in the first place.  Hope this is of some help.   Pam