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What is the proper usage of superscripts in dates (for a formal invitation):
1) full date: Thursday, September 6, 2003 or Thursday, September 6th, 2003.
2) month and day: October 1st or October 1.
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a formal invitation will often write the word out...

"the sixth (day) of september"

check with a local supplier of wedding invitations or other formal announcements and get heir opinion.