<p>“If you presented me with the epsilon delta def. of a limit, I would’ve probably said “ew” as a junior in high school seeing as I wanted to major in journalism. Fast forward a bit and since I’m graduating in the spring as a math major, I’d say you absolutely do not need to understand it when you’re in high school.”</p>
<p>You’re right–he doesn’t need to understand the epsilon-delta definition of the limit while in high school–however, if he were to say, spend an entire summer trying to understand the precise definition of the limit and can’t understand it, then that is a big red flag. </p>