Hi, I realize that this might be a silly question to ask without some proper background so: I'm a rising sophomore who is reviewing Calculus I-III right now. I first took Calculus as a junior in high school under the AP Calculus BC curriculum. I then took multivariate calculus and a semester of differential equations in the following senior year. The problem is, I've stopped retaining everything I learn in math and I was never really that solid on calculus to begin with. It's been a while so my memory of everything was shaky until I my brief review the past few weeks. I've been using Stewart's because that was the same textbook I used in high school. I plan on majoring in math but I'm not quite sure which branch of math I would like to go into. My school seems limited in math classes anyway and we don't have an applied math major; it's just a BA in math and that's it. So in my review I have been skipping over some parts of the textbook I imagined wasn't ever going to show up again. I mostly want to focus on the parts that I need to be solid on for the future. So if math majors or anyone with experience in higher level math can tell me what in Calc I-III I really need to be know like the back of the hand, I would greatly appreciate it.