One of the best math websites that gives answers to questions and problems is WolframAlpha.com. Business Insider notes that the site is "the most useful site in the history of the Internet." The web application bills itself as a "computational knowledge engine."
Wolfram Alpha can give solutions to basic math problems in addition to performing most of the major functions of a graphing calculator, such as calculating logarithms, plotting graphs and solving equations. Users can input the properties of a geometric object and receive a table of information about the object; for example, giving the equation for a parabola yields information about its foci and other key attributes. Wolfram Alpha also gives useful information about chemistry, engineering and even the stock market.