[Retric]

Let’s be clear, if you mean the modern notation, that was was ‘invented’ after the dark ages. So under that definition it’s ~0 people world wide in the dark ages. Excluding independent discovery.

However, if we are talking about the number of people being able to accurately do 1234 / 56 = 22 r 2. That was regularly taught in the Middle Ages with plenty of examples of such calculations being available.