Exactly. Calculus is not hard. Multivariate analysis is not hard. That's because they are very basic math. Proving Poincare conjecture or Riemann hypothesis is

Exactly. Calculus is not hard. Multivariate analysis is not hard. That's because they are very basic math. Proving Poincare conjecture or Riemann hypothesis is insanely hard and completely beyond the grasp of us mere mortals.