Khan academy encourages you to be perfect, not to "master"

I'm a student who is homeschooled and is learning things like History and Algebra 2. Apparently this site is supposed to let you master topics through a whole new way of learning. However, that is simply not the case. My criteria for moving on from a topic is that I must reach level 5 (mastered) by doing the tasks (which are the practices), then taking the unit test. The quizzes are pretty much useless now. I even have a tracker. However, I'm not making much progress. You know why? Because it's tedious!

Okay, so say you take a practice quiz for math. You get two problems, and it says you got nothing. Well, maybe you feel disgruntled, but you carry on anyway, and retake it. You realize those last two right answers were a fluke and you have no idea what you're doing. You watch the video and it helps, albeit only a little bit. After that, you say, "okay, I have a basic grasp of what I'm doing now, I think I can get this." Fast forward to four problems in, and you've got the right answer, you're sure of it. But once you put it in, you forgot to put the x, and now your career is over. And those were some long math problems that you don't want to do again, so you feel pretty discouraged and move on to a different subject. But you're not making any progress in math!

So maybe you did get it right, and maybe you got all the practices proficient so you could go to the unit test. However, you got several questions wrong on that, so now guess what? More questions! And once those are done, you have to do the whole unit quiz again. And those can be over 30 questions on some subjects, like History. Oh yeah, did I mention History?

History is my worst subject. In it, whenever I do a practice quiz, there are so few questions that most of them repeat and I can memorize the answers. I memorize the answers because they talk about things that don't make sense, like "Here's this picture of a ziggurat. Now figure out how government relates to this! This totally wasn't talked about in the videos you watched!" Anyway, here's why history is bad. In the history quizzes, if I do manage to get them right, it's because they aren't those weird types of questions, and they're the good type of questions where I can just click out of the quiz, go to the text (not the century-long videos), ctrl-f to the place that it talks about the question, and sweet, merciful freedom I get.

Please fix your site! It's either your site or my curriculum that needs to be fixed, and frankly, my mom never listens, so please.