thatquiz.org
Amazing MATH practice site. Create and recreate countless quizzes to practice essential skills.
http://www.math.com/students/homework.html
http://www.coolmath.com/
http://www.ixl.com/math/algebra-1
Algebra practice by skill.
http://www.ixl.com/math/grade-6
Practice for many of the 7th grade skills.
http://www.ixl.com/math/grade-7
Practice for many of the 7th grade skills.