But "practice" and "drills" of complex math as done in typical USA schools don't really help many students truly learn the advanced topics. That's why you end up with students who get an 'A' on the test because they memorized the mindless rules to multiply polynomials or calculate the determinant of a matrix but still have no understanding of the underlying math. It was just some weird rules in Algebra to memorize and pass the test. "Mindless plug-n-chug" as people call it.

Repetition of drills do seem to work well for elementary students and basic math like arithmetic: counting, addition, multiplication tables.

But drills is a tool to teach understanding has major shortcomings for later advanced math like Algebra, Calculus, Differential Equations, etc. -- even for the students that got an 'A' on their math tests.

That's why you often get comments on Youtube math explanation videos with variation of, "I studied Fourier Transform in school and somehow pass my exam but this video finally explains what it is! Thank You!!!"

Clearly, there's a huge gap that practice exercises do not address.