Nrich: http://nrich.maths.org/

Ideal for grades 3-8, this site is hosted by the University of Cambridge, UK, and offers a variety of activities to build Math Fact Skills that are updated on a monthly basis. This site provides games, articles, and interactive resources for both students and teachers.

The Math Forum @ Drexel: http://mathforum.org/

The Math Forum is a resource for challenging Math Problems across all grade levels. They offer a wealth of problems and puzzles; online mentoring; research; team problem solving; collaborations; and professional development. Students have fun and learn a lot. Educators share ideas and acquire new skills. This is a subscription-based site, but a trial version is available.

NCTM illuminations: http://illuminations.nctm.org/

Great for grades K-12, this site provides online activities for students and lessons for teachers. Also provided on this site is over 700 web links to other online math resources.

Math Playground: http://www.mathplayground.com/?games.html

Geared for elementary and middle school students, Math Playground has grown to include a wide variety of math topics, from problem solving and mathematical art to real world math. There is also a well-developed library of helpful videos addressing many of the basic math facts. Love to play? Check out this playground full of MATH!!!

Basic Math Facts: http://www.xtramath.org/

For students who need extra support learning and retaining basic math facts, this program is a great way to get that student the extra help they need for free. It also provides friendly progress reports for teachers and students to monitor progress. This would make a great supplement to the classroom or at home.

Interactive Math Games: http://www.dimensionu.com

DimensionU is a video game-based learning resource for K–12 students. In DimensionU, students can access 3D multiplayer educational video games that help them hone their math and literacy skills, connect with friends, and compete and collaborate while learning.

Math Flix is an educational website devoted to effective mathematics instruction. The site features over 800 instructional math video clips and printable worksheets, categorized by NCTM standards. The 4-7 minute clips are from the television show, originally broadcast in Chicago. The off-camera voices you hear in the movies are elementary school students who phoned in to help solve math problems.

Figure This!: http://www.figurethis.org/index.html

Figure This! challenges families to provide interesting math challenges that middle-school students can do at home with their families. Each challenge features a description of the important math involved, a note on where the math is used in the real world, a hint to get started, complete solutions, a “Try This” section, additional related problems with answers, questions to think about, fun facts related to the math, resources for further exploration. Cartoon characters named Polygon, Tessellation, Exponent, Tangent, and Axis illustrate the challenge features. They think math is great!

The Singapore Math: http://www.thesingaporemaths.com/

The main objective of this site is to provide students with an effective learning tool to assist them in mastering the art of problem solving. It covers a wide range of topics and methods so that every lesson is a journey of discovery. This also provides teachers with ready-to-run math lessons for the classroom.

Khan Academy: http://www.khanacademy.org/

Students can make use of an extensive video library, practice exercises, and assessments from any computer with access to the web. Coaches, parents, and teachers can have visibility into what their students are learning and doing on the Khan Academy. With a library of over 2700 videos, students can get a visual tutorial on K-12 mathematics.

Math Vocabulary: http://www.spellingcity.com/math-vocabulary.html

Vocabulary Spelling City has compiled comprehensive math vocabulary lists to make those tricky math words, a snap! Math Vocabulary words help students understand the foundational principles taught in each math concept. Of course, students need to know the meaning of basic math terms before they can learn how to apply them to math principles. From addition words and elementary math to geometry vocabulary and every type of number word in between (algebra vocabulary and statistics definitions are introduced in almost every grade), students can find the right list right here with all the math definitions they need to be successful in math.