Not to mention, I strongly suspect that within the current educational system, the limiting factor is conscientiousness, not IQ. (At least, for high school and most undergraduate systems).
It's true, few people really get integration, but I know plenty of people who are capable of memorizing integration rules sufficiently well to succeed academically - when you get down to it, integral(ax^n)dx=[a/(n+1)]*x^(n+1) shouldn't be hard for a sufficiently conscientious person to memorize and apply. Actually understanding what's going on and being able to derive that from scratch is just an obscure bonus accomplishment.
Why do I bring this up? Memorized integration probably isn't worth the time investment outside of academic success, while an intuitive understanding of integration probably is worth the time investment. If you don't design the indicators of learning carefully, you'll end up optimizing for the wrong thing.
Actually academic achievement is something IQ tests excel at predicting quite well. We also, on average, see clear differences in average intelligence between people with differences in academic achievement, if one was tempted to dismiss the greatest achievement of psychometrics out of hand based on this. This is not to say that conscientiousness isn't another thing the educational system selects for, it is the second best predictor, but it is just that, second best. Formal education taken as a whole from primary school to grad seems to be primarily g load...
The soon-to-be-resigning Dominic Cummings, advisor to the Education Secretary of the Coalition government, has released a 250-page manifesto describing the problems of the British educational establishment ("the blob" in Whitehall parlance) and offering solutions. I post this here because both his analysis and recommendations are likely to be interesting to LW, in particular an increased emphasis on STEM, broader knowledge of the limits of human reasoning and how they relate to managing complex systems, an appreciation for "agenty"-ness in organizational leadership, whole-brain emulation, intelligence enhancement, recursive self-improving AGI, analysis of human interactions on a firm evolutionary-psychological basis, and a rejection of fashionable pseudoscientific theories of psychology and society. Relevant extracts: