Agree! And it's not just limited to math. I used to study for my engineering entrance exams with the Problems in General Physics book by IE Irodov. They were s

Agree! And it's not just limited to math. I used to study for my engineering entrance exams with the Problems in General Physics book by IE Irodov. They were some of the most challenging and creative problems that I have ever solved. They are quite interesting and require critical thinking to solve. Even the problems I later studied in actual engineering courses didn't come any close. The books by Russians in any of the STEM courses are really well written and approach problem solving in a way that most American and/or Indian books don't.