Well, you technically wouldn't necessarily need it, as I have had maths assignments designed where you had to work around from using Pythagoras theorem. But I remember it was hella anoying. So all that made me think (allong with the fact she invented 0) was that as much as I like maths, I would rather not be learning it in their world. (+ since there is magic they probably get by using that to work around what we do with nice concepts)
Though it does make me worry about just how they did their physics. It would be a terribly strange place to me if their physics was also void of many common formulas we use. (I would constantly be questioning the integrity and safety of those mechs+flying devices)
There are gigantic building built here and there in this story, but pythagoras theorem does not exist yet?! I know it just manhwa, but still... it got me thinking hard just about that(￣∇￣").
(Sorry if my english is bad)