The conventional wisdom says that the ACT math section is closer to the math tests you take in high school than the SAT math section is. This argument is based primarily on the fact that ACT math involves things like matrices and trig questions, while the SAT doesn’t.
But both math tests can pose difficulties for experienced math students, and both tests require an approach that’s a little different from the approach you use to do well in math classes.
In short, a student who preps for the ACT by brushing up on trig and matrices can still be plenty confused on the ACT math section, just as she could be confused on the SAT Math section.
For both tests, the primary math difficulties that most students experience come from not knowing how to apply fundamental math ideas to the strange questions that appear on the test.
So here’s the bottom line: if you’re having problems with the SAT Math section, don’t think that switching to the ACT will necessarily solve them instantly. And if you’re having problems with the ACT Math section, don’t think that learning lots of new formulas will solve them.