Grade-2 worksheets - …This is a pretty amazing site. I didn't think it was free at first, but it is. You can sign up if you wish, but it is free as well. Worksheets are for math, reading, and science. The more you click, the more worksheets you find!
Math Playground offers a load of manipulatives for math concepts. The manipulatives are organized in topics such as Visual Division, Pattern Blocks, Percentages, and Equivalent Fractions to name but a few.
www.wolframalpha.com It's kind of a search engine but is not google. It has all sorts of really cool features. May be best suited towards writing a term paper or finishing your math homework, but certainly lends itself awesomely to writing projects everywhere.