Khan Academy will ruin your life. Trust me. Nothing good comes out of it. Don't use it. Don't tell anyone else to use it. It does only harm to your academics. I used to have all A's and 1 or 2 B's on my report card. Then, someone suggested Khan Academy and I started using it right away. Then I got F's and D's on my report cards. I stopped using it ASAP. After trying other programs I got to all A's again. Don't go through what I did. Skip the hard part and NEVER use Khan Academy.