<p>So, I chose to take Math 16A in my first semester at Cal because I thought that I would not major in any sciences. However, right now I want to major in something science related, possibly computer science. I got a 5 on AP Calculus AB in high school and I was wondering if I can take Math 1B next semester, despite taking Math 16A this semester. Do you have to stick with a certain math series once u started it? Will my Math 16A count for units or grades anymore after Math 1B?</p>