An Example space is the collection of examples of a concpet or technique to which you have access at any given moment. NB It has nothing to do with, and must not be confused with, the concept of 'sample space'.

The term 'example space' was coined by Anne Watson & John Mason who observed that very often learners have a very limited collection of examples in mind. For example, if a teacher says 'decimal number' most learners think in tems of one or two decimal places only. A significant aspect of learning mathematics is extending and enriching the space of examples to which you have access. Often an example space is built up from classes of examples, each class consisting of variations of a standard example. The notion of Dimensions of Possible Variation and Range of Permissible Change describe the ways in which different features of an example can be varied, and over what range. Example spaces also include unusual or novel examples which have been encountered. Example spaces also include construction tools for creating more examples from the ones that come immediately to mind. The strategy of asking learners for an example of something, then another, then another is very useful for revealing something of the scope of their current example spaces, as well as serving to enrich those spaces so that next time the concept arises they have a richer range of examples on which to draw. Examples (sic) "adding" usually brings to mind positive whole numbers, but it can be applied to a vast array of mathematical objects, not just numbers.