to learn mathy book stuff well, you gotta do all of:

Unfortunately there are two parts of that process in which learning can be counterproductive:

Mathy stuff takes a ton of time, and if you want to spend extra time doing these things upon your first encounter with each bit of new material, it takes even more. So it is not always possible to do so.

Mathy stuff, like anything but especially, is learned automatically by your mind 'in the background' after your exposure to it; by this i mean that if you encounter some new material and it seems really confusing and then you sleep on it and come back to it, it often seems magically much easier to understand. For this reason i highly recommend trying to give mathy material a pre-read long before you are actually supposed to get to it. It's hard to find time to do this but i think it's actually more efficient, because then more time will have passed between your first and second read-thrus, allowing more background processing to occur in the meantime.