The Mastery System is Khan Academy’s way of giving you feedback about how you’re progressing in your learning journey: what you know, how deeply you know it, and what you still need to learn. You can “level up” on skills in your mission by answering problems correctly.
The goal of the Mastery System is to measure your knowledge, not the amount of time or effort you’ve spent on a particular skill. As soon as our system can determine that you know something, it will update your mastery level accordingly.
Our Mastery System is based on the latest research in education and is constantly being improved. Although the specifics of the Mastery System will continue to evolve, the overall goal will remain the same: to give you a clear picture of your math knowledge.
To read more about Course and Unit Mastery, including how it works with Missions, check out this article.