Memorize.com is a new learning website that allows users to create their own study guides and then share them on the web. The free site assembles user-generated content in three formats -- flash cards, multiple choice, and visual learning diagrams. The topics range from traditional school subjects, such as history, languages, and geography, to less academic categories, such as food, billiards, and television. Users can follow other users and their pages and edit other users' pages to craete their own unique page.
Shmoop, a publisher of digital educational resources, has added pre-algebra to its list of free learning guides. The online Pre-Algebra Learning guides contain hundreds of topics with succinct explanations, diagrams, interactive examples, practice problems, and real-world applications. Pre algebra is Shmoop's first foray beyond its core humanities offerings. At the home page click on the pre algebra tab