Of course, I don't run Khan Academy, so I don't have professional experience in educational-website-whatever-things, but in my experience, the questions on Khan Academy are ridiculously easy and the assignments extremely short. I think that combined with the fact that Khan Academy gives you unlimited attempts should mean that you can get proficiency ratings on everything on the website with very little time investment and/or stress. I think that it's fair to have the system set up this way. I'm also from America, so everyone over here gets A for 90+ I believe (In some systems, that's even a B+)

I agree! It would be nice if there was a setting that said they could miss 1 (or 2) and you consider that a “pass”. Teachers could set it at 0 if they require a perfect score to “pass”.

I think they should go back to getting a number of questions correct in a row to level up. Not such a huge fan of the whole getting one question wrong, and having to do a whole 7 more, especially on unit tests.