- ALEKS math courses online
ALEKS has a full range of individualized online math courses for grades 3-12. They include ongoing assessment and course adaptation to the needs of the student.
- Homeschool Math Practice from MathHelp.com
In addition to its homeschool math courses with a teacher, MathHelp.com offers unlimited free practice for homeschoolers on all topics in Pre-Algebra, Algebra 1, Geometry, and Algebra 2. Select "view courses" to see all the options.
- Khan Academy
Khan Academy offers free online math lessons. Students can work on individual topics, but material is organized by grade levels as well as by upper level courses, and the system helps direct students to appropriate starting points.
- MIT OpenCourseWare for Calculus AP prep
MIT OpenCourseWare includes free prep resources for the AP exam for Calculus.
- Saxon Math Placement Tests
Learning Things has free placement tests for Saxon Math for all levels.
- WatchKnowLearn Videos for Math
WatchKnowLearn catalogs hundreds of free educational videos "Wiki-style" in both broad and sub-categories so it's easy to search. There are sub-categories for topics for all levels of math.