As a high school students I read many times that mathematics is a deductive science. During university years all my courses were taught in deductive way.
My problem is that I have almost never learned mathematics in a deductive way. One exception was Abstract Algebra, but even then only for a part of the semester. Normally, my way of learning was to identify the most important/useful statements and take them as if they were revealed from the Mount of Sinai. Then build from and around them. As much as possible on my own.
I wonder how many other people learned in that way. And wouldn't that way be the best to learn Calculus. For example, we know that
integral from a to b of f(x)dx is F(b) - F(a).
So, d/dx(integral from a to g(x) of f(x)dx) = d/dx (F(g(x)) - F(a)) = F'(g(x)*g'(x)
Another example. Instead of proving (x^r)' = rx^(r-1) the long way, do the following y = x^r lny = rlnx (1/y)dy/dx = r/x so, y' = x^r(r/x) = rx^(r-1)
Student who would notice that for x<0, we may still need some more gymnastics would get 10 extra points.