"This is a list that comprises some of the best math apps and extensions in Chrome store. We have literally gone through hundreds of apps to finally decide on the apps that would make the cut.These extensions are meant to help kids develop math skills through a wide variety of exercises, activities, games, interactive simulations and many more. Some of these apps are integrated with Google Drive and are also available for iPad, Android, and Chromebooks."
From the Open University's Open Learn site.
Identify rotation and translation symmetries in wallpaper patterns. Think this will work well in class, but uses click & drag, so will probably use a wireless mouse rather than the IWB.
Elementary interactive website for students to use on IWB or computer to learn about fractions. Fractions are available by recognizing/comparing & decimals/percents.
This tool enables K-6 students to build visual models of word problems. There are hundreds of built-in math problems covering thirty-six different categories. Videos explain how to model each problem type. The full screen feature makes this application compatible with interactive white boards.
An interactive maze designer - I think that this would be great for an interactive whiteboard. It's part of a site full of interesting pictures, photos and information about mazes. I approached the author, Jo Edkins, about using some of the materials and got a really nice reply. More info about permission for use in schools is here: http://gwydir.demon.co.uk/jo/about.htm
Jo Edkins has also created lots of other webpages - http://gwydir.demon.co.uk/jo/index.htm - I need to start exploring!