Virtual Manipulatives

http://matti.usu.edu/nlvm/nav/vlibrary.html

-Virtual manipulatives by grade level

http://arcytech.org/java/patterns/

-Pattern blocks and fractions

http://arcytech.org/java/b10blocks/

-Base ten blocks

http://www.gingerbooth.com

-Pattern blocks

http://arcytech.org/java/integers/

-Cuisenaire Rods