Is the brain not a physical thing? Do you believe that all human brains are physically and functionally equivalent such that one brain should be able to learn to do anything that another can?

What about those people in this world with genetic abnormalities that affect brain function? Would you expect someone with Prader-Willi syndrome to be able to become competent at mathematics if they only worked hard enough at it? At what point does “hard enough” become “virtually impossible” or even “definitely impossible”?