Understanding of the equal sign at the entrance to algebra: Task design and conversation in math class

We present a study about the meanings attributed to the equal sign, in an algebraic context, by a group of students of secondary school (13-14 years) in Uruguay. We focus on two work sessions we developed with the whole group. The results show that tasks focused on similarities and differences, including those of classifying and those that need to compare and contrast, mediated by a practice of inquiry, generated genuine discussions that aroused the interest of students, which in turn allowed them to approach to conceptual aspects related to the equal sign that contributed to their understanding.