@sweetflo - I think SSAT is a bit “easier” than the ACT/SAT, but there are fewer prep materials available, and the kids who take it are targeting private high schools and so tend to be fairly well prepared academically. That makes scoring a bit tougher at the higher levels (say, over 85% range) because a few wrong answers can cost you. Nevertheless, the math in particular is less difficult than that of the SAT/ACT, though perhaps a bit less straightforward than the ACT. SSAT also has a verbal section (at least it did when S21 took it), which you either love or hate.
@ChezCurie - I certainly did not want to mislead anyone. While technically 4 of the OHS semester courses available at the university level do not require calculus as a prerequisite, at least 3 of them ordinarily require calculus when offered in colleges and universities: number theory, discrete math, and geometry (here lattice point geometry, which relies heavily on combinatorics). These are not basic courses; for instance, the number theory course uses the Stark text. At universities and colleges, all these or similar courses usually require successful completion of the intro sequences in calculus (at the BC level) in order to ensure that the students have enough sophistication to take them. I probably should have just said that OHS offers 5 years’ worth of math beyond the typical high school level!