Do you know a good math learning service?

Question

Mathematics

Again, I am entering the master's program, in mathematics 0 ^ 0
Now, of course, I understand that I am unlikely to prepare in a month, since I read most things like a Chinese letter, because it is written by no means for understanding from the basics. And I can't read the entire book.
Essence: we need a task-service, where you can find many examples of the application of theorems, their consequences, laws, etc. with detailed solutions for understanding.
Many thanks to everyone in advance.

Answer 1

mathprofi.net

Answer 2

For some reason, the Euclid game closed. There is such a problem book: sciencevsmagic.net/geo/# but it, apparently, is not about that. But if you search for "interactive geometry problems", then it gives a lot of things, you can dig into the results.

Answer 3

>>Do you know a good math learning service?
Yes, Algebra for the 1976 edition, if anything ...