The actual question is, if you presented an undergraduate-level calculus problem to a human who is considered intelligent but who was never given an "understanding" of math in school, would the human be able to solve it? Why or why not?

If so, what exactly would you call the process by which the intelligent human solves the math problem that he or she does not initially understand?

Whatever you call that process is what a reasoning model does. You don't have to call it "reasoning," of course... unless you want other people to understand what you're talking about.