Irruption of a concept in the curriculum: primary teachers define and apply the concept of measurement estimation

In this article, we present a study of certain aspects of the mathematical knowledge for the teaching that teachers possess about the concept of measurement estimation. We study how teachers define and apply this concept which has been recently introduced in the Chilean curriculum and on which teachers have not received specific training. A survey was applied to 112 in-service teachers in their continuing training in Santiago de Chile. By means of a qualitative-descriptive analysis, we noted that the disciplinary knowledge on the concept of measurement estimation is poorly developed; teachers do not know the key aspects of the measurement estimation and confuse it with other measurement activities such as measurement with nonstandard units.