<p>It depends on what you want to do. For many fields, a good working knowledge of calc is really useful. So it seems like a bad idea to recommend that you skip single-variable calc.
On the other hand, I would recommend against 1a and 1b if at all possible. They’re not very good or fun courses - they’re not terrible, but no one (who I know, at least) really likes them.
I took 21a in the fall after a full year (two summers and one academic year, actually) away from any kind of math and after high school BC calc, and it was fine. All you need is basic integration techniques - the most complicated it got was, like, integration by parts.
But like I said, basic calc is useful for a lot of things, especially if you’re going into math (obviously), science or even econ.
My recommendation would be to self-study the BC curriculum over the summer and then to take a look at the 21a textbook, which the course follows pretty closely. (I’m pretty sure it’s the Stewart MV calc book, but this info will be available on the course website before long.)
**Keep in mind that you can’t shop Math 1a, 1b or 21a, since they’re taught in section and don’t start until the second week of classes. You can switch before the add/drop deadline, but that’s often very inconvenient, especially in classes like 1a, 1b and 21a that have a problem set due during every class (THREE a week).
You can shop APPLIED 21a, which might be easier and is another option to consider.
Good luck!</p>