Glad someone agrees. I love the old mastery challenges because oftentimes I don't need the video or article to do the problem; I can figure it out on my own. It forces me to actually learn instead of memorizing stuff I won't use.

You are so right! When they added the Course mastery system, I felt like it was harder to use than missions. Also, it's nice to be able to see a little circle indicating the percent completed of the course. The recommended skills were cool, as were the way to master them (mastery challenges). I don't understand why they are taking them away....

I'm guessing the World of Math page is also going to be removed. Shame, seeing that percentage sign indicating how far away I am from achieving 100% in all of the maths is going to be missed.

The Course mastery is just terrible. The blocks are so much more accessible. I have a test to study for and this is just terrible news.I might have to go somewhere else if this happens.

I'm so sad!!!

I use missions exclusively. I will be sending an email to KA to let them know I am very sad. As someone who is motivated by percentages and seeing how much I have left, this is going to be detrimental to me. 

Hi Deanna,

Thanks for the feedback! Feedback like this is really useful for us as we continue to improve the Course Mastery system.

The Mission system has been with Khan Academy since 2014, so removing the Mission system was definitely a difficult decision for us. One of the main reasons why the Mission system is being removed is because it is simply not maintainable in the long run. The Mission system is written in an old code base that’s caused slower load times and bugs that just aren’t sustainable.

That being said, we've worked hard to make sure the new Course Mastery system is more efficient and sustainable than the old Mission system. We've also worked to make sure that Course Mastery has all of the same functionality that was available in the Mission system, but with a more structured format.

Here are some of the popular features of the Missions, and their replacements in Course Mastery:

• In Missions, learners can take Mastery Challenges to test out of skills they already know, and to identify which skills they should work on. In Course Mastery, learners can take the Course Challenge, Unit Tests, and Quizzes before completing the previous content. This will increase the learner's mastery level for skills they already know, and recommend practice exercises and videos for missed questions.
• In Missions, learners can use Mastery Challenges to review concepts that have previously been mastered. We've just introduced a new Spiral Review feature for Course Mastery that allows learner's to review concepts they have already mastered in the course.
• In Missions, learners can view their progress through the circular progress indicator and grid of skills. In Course Mastery, learners can view their mastery progress for the course and each individual unit from the main course page. Clicking inside the unit allows the learner to view their mastery level for each individual skill.
• Course Mastery also offers a more structured approach to learning. The videos and exercises are listed in a set order, whereas there was no clear order for the skills in the Mission view. However, the exercises and units in Course Mastery can still be completed in any order like the Mission system.

If you have any additional feedback for how we could improve the Course Mastery system to better fit your needs, please continue to share here!

Thanks for posting! Let me know if you have any additional questions!

If the code is out of date, just build it again from the ground up. Maybe remnants of the old code could still be used to make the process of re-coding it easier.

Lime Tuna, Yes I agree with you that they should just rebuild it with up-to-date code. And if the Missions were only in the Math subjects, then why not create them in the other subject areas? We could have World of Science, World of Art History, etc.

I absolutely agree!

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