What exactly is your question, which math class to take? It really depends on what you are trying to do. Math 1 is PreCalculus and Math 31A is Differential/Integral Calculus. You have to take Math 1 first (prerequisite) before you can Math 31A. The 3rd final class in that series is Math 31B (Integration Calculus), which you take after Math 31A. This is all listed on UCLA website.