If you are reading this page, and have some time, I would appreciate help in organizing this page into useful categories! Thanks.

Recommended by a parent: http://ca.ixl.com/     

It is based on the Ontario Curriculum however the lessons are applicable anywhere.

I checked out the Practice section and it's got a great approach.

• http://www.tenmarks.com/index.html - assessment aligned to common core
• http://plus.maths.org/content/ Free online publication highlighting the practical applications of mathematics. Includes mathematics-related news articles, podcasts, and mathematics puzzles designed around "real-life" scenarios.
• MathGrade: everyday math as podcasts
• Dan's MathCast: more math podcasts
• STEM Resources - Science, Technology, Engineering & Math) Education Resources
• http://www.syvum.com/math/ - quizzes   (also http://www.syvum.com/teasers/)
• and http://www.syvum.com/math/trigo/ (trigonometry)
• http://teachingcollegemath.com/?p=1898 - good advice for high school, too
• HotChalk - http://www.lessonplanspage.com/Math.htm
• UCCP Open Access Lessons: http://www.ucopenaccess.org/ 
• http://www.hippocampus.org/ 
• Create a Graph
• StudyJams
• Univ of Tennessee Math Archives
• Free Lectures through video: http://www.khanacademy.org/
• Short how-to videos at the educational site, Next Vista
• http://adifference.blogspot.com/
• http://calculationnation.nctm.org/   - recommended by Free Tech for Teachers
• http://illuminations.nctm.org/
• http://www.mathpickle.com - pose 1,000,000 questions to your math students, videos explaining math principles
• http://nlvm.usu.edu/en/nav/topic_t_1.html - a collection of manipulatives in digital format
• http://nrich.maths.org/frontpage
• Calculus on the Web An internet tutoring utility for learning and practicing calculus
  Visual Calculus Short descriptions and examples for limits, derivatives, and integrals. Various plug-ins are needed to view some of the pages
  Math Teaching Resources Java programs, flash movies and interactive templates
  National Library of Virtual Manipulatives Virtual manipulatives for various mathematical topics
  Interactive Mathematics Project Various Flash activities demonstrating math concepts
  The Connected Curriculum Project Interactive learning materials for math and its applications
  Java Script math applets| Middle School | Trigonometry | Calculus | Vector | Complex number | Conics |
  Equation Match Find matching pairs of equations by solving for x in each equation
  Math Open Reference Using interactive tools and compelling animations, it provides an engaging way to learn and explore the subject
  E-examples for Math Standards aligned lessons from Illuminations, a rich math resource from NCTM
  Shodor Interactive creation, collection, evaluation and dissemination of interactive Java-based courseware for exploration in science and mathematics