The goal of the paper is to present how, using an analysis of a pupil's mistakes, their difficulties in solving word problems can be identified and their causes detected. The word problem that is the tool of our research was chosen to enable monitoring of pupils' difficulties in the following parameters: the chaining of thinking operations, the non-standard nature of the tasks and the interdependence of the success of a pupil's solution with their ability to understand the text (part of reading literacy).
Our results show that it is reading comprehension that is a key source of difficulties. A description of the causes of individual pupils' difficulties will subsequently enable an individualized re-educational procedure to be established.