bruh I have dyscalculia( It is sometimes colloquially referred to as "math dyslexia") But I can easily understand latin numerals and you are trying to tell me japanese who are nerds can't understand something so simple?
If you’re talking about roman numerals, maybe it has something to do with the fact that they’re letters and not numbers? I’m guessing because that actually sounds kinda neat. Gonna go look that up later. Generally speaking, no, it’s math as a concept and not just “numbers”, and people seem to struggle just as much with roman numerals. This guy’s just lucky i guess.
But also, you were almost definitely taught basic roman numerals in school for
reasons, and they likely weren’t, so unless they went out of their way to learn that stuff of course they don’t understand it.