When a student – for example in a task – meets a concept, parts of his/her concept image will be activated, the activated part is called the evoked concept image (Tall & Vinner, 1981). Since it is not possible to directly observe concept images, we need to search for traces of them in utterances from the students. Such traces can only be expected from the evoked concept images. Hence, what is possible to observe are traces of the evoked concept images and through these traces we can discern components of the evoked concept images