So i think i want to be a math teacher at a highschool. But i want enough math skill to never have to look at the textbook for a lesson plan. I want to have enoguh proefficiency in math to just start writing down notes on the blackboard just by using my head. My friends tell me profs do this all the time (I just graduated highschool). I would love for my life to be that easy. Does anybody know how long it will take to get this skill?