Gives a precise definition of scientific notation; included is how to determine the order of magnitude of a number with respect to scientific notation.
This site walks you step-by-step through simplifying an expression under a square root sign. Type your problem into the "math solver," and your answer, complete with a full description, is provided.
4th world information, excellent virtual library including Americas, Africa, Asia, Europe and the Pacific. A good resource for hard to find information.
This site explains how to round whole numbers to the nearest hundred thousand. Gives practice and games to practice this skill which are fun and helpful on the subject.