on October 5th
💡 Memory tip: Dates use plain numbers + the month in the genitive: πέντε Οκτωβρίου. Only the 1st uses an ordinal: την πρώτη Μαΐου.
“Γεννήθηκα στις πέντε Οκτωβρίου.”
I was born on October 5th.