I find it helpful to first learn the theory via 3blue1brown
I'm currently working through the bookofproof math problems found here
It goes into how to actually write mathmatical proofs / discrete math which I believe is extremely important to any math branches and computer-science in general.
I was lucky to have a great foundational math background in highschool, my calc 1/2 teacher was considered one of the best in my state. I practiced at least 30 problems every night in that class for 2 years