Basically all of calculus, but especially multivariable and differential equations. I was first introduced to them in high school and again in college, I strugg

Basically all of calculus, but especially multivariable and differential equations. I was first introduced to them in high school and again in college, I struggled with them in high school, but breezed through them in college. Not sure if I just got smarter, worked harder, or some combination of the two :)