The National Library of Virtual Manipulatives (NLVM) is an NSF supported project that began in 1999 to develop a library of uniquely interactive, web-based virtual manipulatives or concept tutorials, mostly in the form of Java applets, for mathematics instruction (K-12 emphasis). The project includes dissemination and extensive internal and external evaluation.
Matti Math:
The NLVM Computer App is an enhanced offline version of the NSF supported National Library of Virtual Manipulatives (NLVM) for K-12 mathematics. It boasts an NSF supported library of uniquely interactive virtual manipulatives for K-12 mathematics instruction. Features include: Print Image, Save Work, Configure, and Make Activity. Install on any Mac or Windows computer.
Learning Lovers.org 
mattimath does not open, and NLVM doesn’t work–no matter which browser I use or how much I tinker with JavaScript settings. This is very disappointing.
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Hi, Marsha, thank you for letting us know. We are not responsible for the external websites we recommend. Thanks!
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