Wiktionary
number systems
n. (number system English)
Usage examples of "number systems".
In other words, the people who not only understood the number systems and astronomical procedures that we still use today, but who developed them, couldn't have seen what they say they saw because it contradicts what boils down to faith in a dogma.
How often had I seen Belbo, after office hours, running programs to check Diotallevi's calculations, trying to show him that at least Abu could give results in a few seconds, not having to work by hand on yellowing parchment or use antediluvian number systems that did not even include zero?
We would find ourselves handicapped if we were still to use the Babylonian, Mayan, Egyptian, or Roman number systems.