I keep mentioning that, in my opinion, non-college mathematics teachers generally only know enough math to get through the end of the material they're teaching

I keep mentioning that, in my opinion, non-college mathematics teachers generally only know enough math to get through the end of the material they're teaching in any given semester. I don't think they're capable of teaching the material from multiple angles, which seems necessary in order to instill a fundamental grasp of the material.