I “discovered” this program about a year and a half ago. A colleague told me to look up “Furbles” which is an excellent data representation program using little creatures whose characteristics can be changed and represented graphically.
On going to the website www.ptolemy.co.uk I found that there was another program called “Primitives”. This was a real find. I think it is a work of internet genius. It represents all of the numbers by colour coding them and then allowing you to see how they factorise (or not… since if they can only be populated by dots then they are obviously prime!).
I have used this free program with many children (aged 7 to 11) who absolutely love it. The reason is not to do with the numbers and their properties but the sheer artistic beauty of the representations of the numbers.
I would urge you to take a look at it and then, if you are brave enough, let the children play around with it… do not teach them anything! Let them explore and find out about the multiples, factors and division facts.. you will be surprised at the results but most importantly you will get them to see the joy and fun and beauty of numbers and that is something that no boring textbook or interactive whiteboard program or worse still you telling them a fact will ever have.