"I don't see why I would, but then again, even I can't predict all possible situations in the future. I've never even entered a public school, so maybe I've missed out on something important. I consider it unlikely."
Yes, even if school had been mandatory in Beyblade world, Ryuutaro would've probably gotten a private teacher. He used to be a spoiled kid like that.

And he actually didn't know about the things taught in school. He knew writing and reading and magic, it was all he needed. Maths outside of beyblade physics for example was something that he had remained completely oblivious of in his life. He'd just never needed these things.