Do you need help with difficult courses?
The Khan Academy is an organization on a mission. They are a not-for-profit organization with the goal of changing education for the better by providing a free world-class education to anyone anywhere.
All of the site's resources are available to anyone. The Khan Academy's materials and resources are available completely free of charge.
There are over 2,100 videos, covering K-12 math, science topics, algebra, biology, calculus, chemistry, physics, and includes the humanities with playlists on finance and history as well. Each video is a digestible chunk, approximately 10 minutes long, and especially purposed for viewing on the computer.
Khan Academy is a great resource for students and teachers!