Including already Mastered Skills in Mastery Challenges can be demotivating

I agree with you. This is one reason why I liked the old Mission Mastery system better. In the old system, if a new skill was added, after you did the practice exercise for it, you could go right to the Mission and get this skill tested. Sometimes, to make the Mission exercise have more than one question, questions for skills already mastered in this course or earlier ones were thrown in (and when this happened, getting one of them wrong did cause you to lose mastery, but you could go back in to the Mission and level back up to mastered without getting a whole unit test again).

Retakes of unit tests should mainly consist of problems/questions for skills not yet mastered. The second most annoying thing about the unit tests is that sometimes there are fewer questions than the number of skills the course contains, but the one skill you still need to master is not included in the question set you get on the retake. For example, there are 35 skills and a 34-question unit test, you got one wrong the first time through, and that one skill you missed is the one skill that's left off the retake.

This is still a problem. I'm working through high school physics as an adult and it's really easy to make a sign error or rounding error which is compounded by some of the answers. One answer which went to 10 places required a precise decimal while most require rounding to two sig figs.  

After unit 1 I'm giving up entirely on the scoring system. These gamification metrics can be very motivating for me, but losing points over sign errors when I essentially understand the concept just makes me not care about the points.

Subtracting points is a penalty, please find a penalty-free way to gauge and gamify progress.

Looks like folks have this issue for years but no way to mitigate it.

Mastery challenge keeps on repeating skills from first unit even if skills in that unit have been mastered. My kid is no longer interested in doing mastery challenges. Is there any way to contact Khan Academy team to make it cover other units in the course?

Hi Mahesh W,

Thank you for sharing your thoughts on how our Mastery Challenge content could be improved. 

We'd love to gain a better understanding of your experience. Could you please submit a support request in our Help Center? Here's the link: http://khan.co/KA-support. 

Warm regards,