The National Library of Virtual Manipulatives (NLVM), started in 1999, serves as a virtual library of interactive, web-based virtual manipulatives for mathematics instruction. NLVM offers manipulatives in Number and Operations, Algebra, Geometry, Measurement, and Data Analysis and Probability. It is organized by strand and grade level for quick and easy searches. The library is comprehensive including hundreds of resources for every subject, concept, and skill. Teachers can use NLVM in their classrooms on interactive whiteboards, projectors, or in computer labs to enhance their mathematics classroom and actively engage students. The manipulatives help students visualize mathematics relationships and concepts.