The weird thing is how rarely approaches like the one you describe here are applied. It's not exactly a secret that simply providing the answer to math question

The weird thing is how rarely approaches like the one you describe here are applied. It's not exactly a secret that simply providing the answer to math questions is great if someone gets them all correct, but nearly useless when someone gets them wrong. It's a problem that's been solved before - in a classroom, the traditional answer is working through the problem on the board and hopefully students are following along. Accompanying books with videos that work through the problems has been done at least since we had VHS. So why are there still so many bad study books?