well, we borrowed the zero from the Arabs, which allowed us to write numbers like 20, 30 etc. The Romans did not have zero so 20 had to be written as XX (ten ten) etc., which makes it cumbersome.
And they do look like them, but in an impressionistic you-have-to-squint-at-them sort of way! Both sets have evolved from a common ancestor. Think shetland ponies and zebras.