FREE Math Workbooks and (subscription) Math Help
Hotmath.com has a few FREE online workbooks to help students practice math problems. They include Middle School math, Pre Algebra, Algebra 1, Algebra 2, Precaluclus, and Calculus. In addition to the free workbooks, hotmath.com is also a subscription website where you can view solution to the question is any number of math textbooks that you may already own such as Algebra 1 (Applications, Equations, & Graphs)
or McDougal Littell Algebra 2: Pupil's Edition. They support over 300 textbooks. They also have subscription based video lessons.