I think most people in the past 45 (at least) years have learned and referred to our numeric system as the "hindu-arabic" system. Zero is maybe one of the most important discoveries (or inventions, if you prefer) of all time. In the west, we became familiar with the Arabic number system via Fibonacci's "Liber Abaci" or "book of counting" (and a few other works). He had a hard time selling the idea to the educated people of his time before the book - scholars were still using roman numerals. Fibonacci's father was a merchant who had payed a "blackamoor" to tutor his son.

On a slightly different topic, but also interesting, some ancient cultures (egyptians, e.g.) used only unitary fractions; that is, fractions in which the numerator is exactly 1. So they would not write 5/6, but 1/2 + 1/3.

The idea of equations is fairly recent (I think it was like something like the 1500s or 1600s). Prior to that people would write out word sentences.

A lot of the stuff that we take for granted in math today took a very, very long time for people to figure out.