They would know the Pythagorean theorem I would think, but in what other ways was Roman math advanced?
I've heard they weren't as advanced as the Arabs of their era, because of their weird number system
This question is too absurdly broad. Do you mean the Romans of the Monarchy, Republic, Imperators, Empire? Or do you mean the Byzantines and all of their thousand years of history? Roman math changed a lot over those millennia.