calc ab in high school
at UCLA, depending on your major, they would put you in different math courses. there was one track for physical sciences, one for life sciences, with the physical sciences being on a slightly tougher track. because i majored in biochem and not bio, i was placed into the physical science track, so i had to take the 31-32 series instead of what was the 3 series (could be a bit mistaken on the exact numbers).
for biochem, i basically needed calc AB (would have been 31A at UCLA), BC (31B), and then a pretty basic multiviariable calc (32A). i found 31B to be challenging. 32A actually seemed easier. they really toned down the complexity because it was multivariable, so a lot of the problems seemed pretty simple