Sure. I’m pointing to the difference between making sure that you can do proofs (not necessarily reconstruct the particular ones from the textbook) and exercises, and actually reconstructing the proofs and doing the exercises. Getting to the point of correctly ruling the former can easily take 10 times less time than the latter. You won’t be as fast at performing the proofs in the coming weeks if need be, but a couple of years pass and you’d be as bad both ways (but you’d still have the concepts!).
Sure. I’m pointing to the difference between making sure that you can do proofs (not necessarily reconstruct the particular ones from the textbook) and exercises, and actually reconstructing the proofs and doing the exercises. Getting to the point of correctly ruling the former can easily take 10 times less time than the latter. You won’t be as fast at performing the proofs in the coming weeks if need be, but a couple of years pass and you’d be as bad both ways (but you’d still have the concepts!).