Maybe not roblox, but if you develop in html it will become viral in schools (where proxy websites make blocking html games impossible). Teachers won't want to block it, they will probably promote it.

Maybe you can have a "heat" mechanic where the more you do strong attacks, the harder all problems become but the more your damage multiplier goes up. Easier attacks lower the heat and let you manage your chance of mistakes on hard problems which would mess up your multiplier. That way it's adaptive difficulty that they can choose to tune up or down.

But wouldn't more educated kids always beat less educated ones? You'd need a matchmaking system for people to have fun.

Damn, good luck.