Learn using videos, interactive exercises, and in-depth articles in math (arithmetic, pre-algebra, algebra, geometry, trigonometry, statistics, calculus, linear algebra), science (biology, chemistry, physics), economics (microeconomics, macroeconomics), humanities (art history, civics, finance, US history, US government and politics, world history), and more (including computer science principles)!
EdX is another leading online-learning platform that is open source instead of for-profit. It was founded by Harvard University and MIT in 2012, so you know that you’ll learn about cutting-edge technologies and theories. Today, edX includes 53 schools. You probably can’t go wrong with the free Introduction to Computer Science from Harvard University.