freeCodeCamp
Our pickLearn to code free, with certificates.
The best Khan Academy alternative is freeCodeCamp: Learn to code free, with certificates. Other good options are MIT OpenCourseWare, Coursera, Desmos.
Learn to code free, with certificates.
Real MIT course materials, free.
University courses. Certificates cost money.
Free graphing and scientific calculator.
Solves math and science questions.