The article presents a teaching experiment contextualised in three schools in the city of Temuco, Chile. The study included courses in primary and secondary schools, and was planned to address a problem of low reading comprehension among the pupils identified in standardised tests like the Education Quality Measurement System (SIMCE). The problem arises especially from the lack of specific reading strategies to facilitate comprehension by the pupils, especially though inference, interpretation and reflection. The object of this teaching experiment was to impart to pupils a grammatical summarising strategy to enable them to schematise and grasp the information in a text, allowing them to gain reading skills. To do this, a summarising technique was developed and taught to teachers and pupils in municipal-public and subsidised schools; the results were assessed through reading comprehension tests focused on the skills of reflection on the text and relation and interpretation of the information. The principal finding of the experiment, based on the levels achieved in the tests, was that the summarising technique helped the pupils to locate information, which was reflected in their increased ability to draw inferences from and reflect on the text.