If you studied math, or if you have any kind of respect for the mere concept of rigorous proofs, then these kinds of resources will leave you deeply dissatisfie

If you studied math, or if you have any kind of respect for the mere concept of rigorous proofs, then these kinds of resources will leave you deeply dissatisfied. If you want to refresh your math, take an elementary result of any particular discipline, e.g. existance and multiplicity of eigenvalues in linear algebra, or uncomputability of the halting problem, and see if you can prove it yourself from what you still recall. You will have to look up on definitions and theorems on the way there, refreshing your skills.