At this point it's turtles all the way down.
You have to arbitrarily decide where to end: typical 5-year-old, typical high-school student, typical math professor.
What people mean by "simple terms" is "simple terms that I understand".
That's what it looks like if you only look at the formula. (And why I'd say that formulas are not an "objectively simple way of expressing something*)
If you can somehow keep in mind what the formula is supposed to represent, the operations on characters will let you find some insight about that thing and will stop standing only for itself.
Also, mathematical formulas are essentially a different language. If people don't speak it, then it's a moot point.
> Feynman was also quoted as saying:
> I think I can safely say that nobody understands quantum mechanics.
Trying to explain a concept in "simple terms" forces you to view it in terms of its connection to other, well-known phenomena.