What a shock it was for me to realize that I did not even understand the idea of 'function', the main object of study in calculus. Of course there is some memory work in mathematics, but every memorized fact must be reinforced by an understanding that itself is not memorizable. That understanding becomes a part of the learner in a way that no memorized fact ever can. It cannot be forgotten. Thus, there is great danger in memorizing without understanding.
Students sometimes fail to remember the context of the memorized formula.
I will give two examples. As your instructor this semester, I think the way I can be most helpful to you in learning the course content is to work with you to develop your understanding of the ideas of the course.