Khan Academy "Saved Exercises" feature

Hey guys! As I've been preparing for SAT, I encountered one problem that most of the questions here are easy, but my practice tests are not. However, there are some hard exercises here either that I should usually work on for long or just answer to incorrectly due to concept problems. And I'd like to be able to SAVE those exercises for future practice - because they are sort of your loopholes. And the more you study EFFECTIVELY (by focusing on your weak parts), the more efficiency there is. I thought this feature would be effective across all courses, especially when preparing for your finals or similar. (the sign "save exercise" might be near "marker" sign when practicing SAT questions here)

And those saved exercises, I think you might be able to use them for brief overview of the material you've mastered, because for SAVED exercises, i think feature of adding PERMANENT notes will be useful. You might save the most relevant exercises 1-2 per some lesson or similar, describe how you solved those and look through them when test is coming or you haven't studied anything for a long time and it'll be "get-my-knowledge-back" thing (and also your way of solving might be different from Khan Academy's so it'll give you only the most relevant information).

And, of course, you should be able to have a quiz out of those saved exercises, you know, TO PRACTICE (I don't know how and i know it'll probably unfeasible, but i'd like to have some sort of AI which can make the exercise really similar but with different numbers for Math and different content for R&W, I guess)

Just my idea, don't know how much useful it'll be generally, but for me it certainly will as I've been mostly "saving" those type of exercises by screenshooting which is incredibly inconvenient (apologies for my English)