We've always found algebra a very difficult subject to teach. While it has many connections to the real world, the approach taken in most high school (and college) algebra classes is very abstract. Our online reference gives quick summaries and examples of all the major topics that you'll find in both a first and second year algebra class.
The algebra reference is divided into categories (look at the menu to the left) and subcategories. Clicking on an option in the category menu will display the subcategories that correspond to individual articles.