"I do not wear a belt."

Translation: Εγώ δεν φοράω ζώνη.

[SassanSanei]

I translated this as "Δεν φοράω μια ζώνη" but was incorrect. Is the μια wrong or optional?

[D_..]

I can't think of a better way to explain it, so I'll just make the following suggestion: when ένας/μία/ένα are the indefinite article, not the numeral, drop it in sentences with negation. "Δεν φοράω μια ζώνη" = "I am not wearing one belt" or completely unnatural, therefore wrong I'd guess, with the indefinite article.

[SassanSanei]

Ah, that makes sense now. Thank you!