How do you say how are in Roman?

There isn't a direct translation of "how are" in Roman numerals. Roman numerals are primarily used for representing numbers, not for forming words or phrases.

If you're looking to express "how are you" in a way that could be understood in Roman times, you would need to use Latin, the language spoken by the Romans. The phrase "how are you?" in Latin would be:

"Quid agis?"

This is a formal greeting and a way to ask someone how they are doing.