National Library of Virtual Manipulatives
The National Library of Virtual Manipulatives website is hosted by Utah State University. It has up to 100 virtual manipulatives, mainly java based, that are categorized by grade level and mathematics topics. The mathematics topics categories include Number and Operations, Algebra, Geometry, Measurement and Data Analysis and Probability. These categories are closely related to the five strands of the Revised Primary School Mathematics Curriculum – Number, Algebra, Shape and Space, Measures and Data. Each manipulative has a parent/teacher information button giving details of the learning objectives of each manipulative and an instructions button which gives detailed instructions how to navigate and use the manipulative.
The manipulatives which are very visual and colourful can be used in the primary classroom in a number of different ways from whole class teaching particularly if the teacher has access to a data projector and/or an interactive whiteboard to small group teaching and peer teaching. One of my own favourites from the NVLM site is Base Blocks which can be used to demonstrate and teach addition and subtraction including decimals. I believe teachers will find this manipulative very useful when children are moving on from using concrete materials but yet need a little scaffolding because they are not yet quite ready for abstract problem solving