The Khan Academy is a website that specializes in online learning and studying. Any user can sign up on the site for free and then is able to look up any subject that they are interested in learning about. You can look up topics by grade level or by individual subjects. There is a vast amount of information to investigate and study by hovering your mouse over the subject headline, allowing you to see all of the possible topics. For example, by clicking on the Trigonometry link on the top, you can see the site’s definition for trigonometry as well as samples for the topic at hand.