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
The preminent Internat publisher of literature, reference and verse providing students, researchers and the intellectually curious with unlimited access to books and information on the web, free of charge.
Bartleby.com looks like a cool site. Has unlimited access to books and information on the web. Feel free to share with anyone who may be able to use it.