Why can’t I get a full point when I complete all questions in a math exercise correctly?

Hi!

Here's an article that explains how the mastery system works, including how to level up each skill: https://support.khanacademy.org/hc/en-us/articles/115002552631-What-are-Course-and-Unit-Mastery

If you have any further questions, please don't hesitate to ask!