I see in the rules that math games and other educational games are not allowed to be requested, but a quick search shows that there are numerous math related games already submitted and approved on this site. So it is ok to request a math related game then(I'm talking basic arithmetic here, like 2+3)?

If this is an actual GAME that also involves math, that is okay. But generic math/puzzle games on the web are not allowed. Also, most of the generic math games on the site were approved years ago, before the rules got stricter.

Yes, I'm thinking of requesting a RPG/Adventure 2D game(web-based) that is also math-based. It's a game aimed for a younger audience for them to learn basic math, but it has speedrunning potential(in my opinion). Do you think this is an acceptable game to submit?

Maybe. Request the game and then you can see if site staff accept it or not. (After you read and comply with all other game-request rules)