This question is about Mathematics only. My fore thought is that courses is usually built on textbooks. But their contents is not as much as those in the textbooks. There are less problem sets, skipping chapters. Is it true that you can learn more by self-study with textbooks rather than college courses? Given that one could gather the help from the internet?

This question is about mathematics only. My forethought is that courses are usually based on textbooks, but they have less content than the textbooks. There are less problem sets, and chapters are skipped. Is it true that you can learn more by self-study with textbooks rather than college courses? Given that one could find help in the internet.