It's just calculus where admittedly my own education stopped but it's still very helpful in finding values in real-world things like change of value in time. I still hope to one day develop a working knowledge of it, myself. u/...mir below me did a good job of summarizing the two main introductory concepts in much the same way i've read others simplify and describe the subject in classic 100+ yr old books like "Calculus Made Easy by Sylvanus Thompson." I suspect it's not as intimidating as it seems once a person gets past some basic fundamental concepts.