Andrew Zhang 张灿诚

1. Cộng đồng
2. Content Requests and Feedback

May we please say that people should not be able to post silly 'questions' to the discussion section of a course? All you see are questions or 'nonquestions' that have nothing to do with the topic ...

1. Cộng đồng
2. General Khan Academy Questions

I can guess what the Black Hole Badges are (2 of them). All of the badges that have energy points as reward are for mastering a number of unique skills. Two of the Black Hole Badges have a lot of ...