Probability simulations
Planetqhe is a site by David Kay Harris dealing with probability. There are Excel spreadsheets that present problems in probability in a novel way, including two stage tree diagrams.
The presentation is different to the usual one in UK GCSE textbooks – Harris is head of Maths at the International School of Toulouse and the site is in English for use by Baccalaureate students.
The Web site navigation is a tad confusing (inconsistent use of frames) and the multiplicity references in the text to the Amazon store is perhaps sending a very ‘heavy sell’ message (I have no issues with sponsorship in general – just how you integrate the marketing message into the site).