Lesson aimed at contributing to the teaching-learning process of the arithmetic mean or average, in first-year secondary school students in the Valley of Mexico.

Abstract

This research explains the mechanisms used by first grade students of secondary school No. 144. "Juan Escutia" in the State of Mexico, to learn the concept of arithmetic mean or average. The methodology used was the exploration of the notion of the concept of average, through a questionnaire applied to 84 students, to find out the difficulties they present in carrying out tasks related to the subject. Subsequently, an analysis of the answers issued was elaborated and they were classified through the SOLO taxonomy. The result shows that almost 30% of the students have problems identifying what type of operations they should perform, this indicates a low level of abstraction in this task.