As a group, the Greeks, especially the Attic Greeks, of the 5th century BC were probably the smartest people ever to breathe upon this earth. They had no television, no radio, no Internet. With such few distractions, they found their diversion in thinking.
I’ll not argue with you on how bright the ancient Greeks were. They were very smart people so I am sure they could multiply and divide. I was just pointing out that without a position based number system. multiplying and dividing ain’t easy. lol. They had a pretty close value for Pi too, 22/7 IIRC.