wolframalpha.com

wolframalpha.com

Wolfram Alpha is a website where you can find specific answers to questions or topics you have.  Pros:
 * Gives specific answers to your questions
 * Provides sources

Cons:
 * Takes a while to search
 * Sometimes can't answer your question if it's vague or not in the database

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I give it 4.5 stars.

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