Abstract

A playful learning sequence on informal inferential reasoning is presented, consisting of two lessons that integrate key aspects and concepts of this reasoning. The sequence was designed by primary school teachers within the framework of a Lesson Study Group (LSG) and implemented with 23 students aged 8 to 9 (grades 3 and 4). During the lessons, students made predictions, recorded data, obtained samples, and compared them through repeated sampling. Through analyzing teacher-student interaction episodes throughout the sequence, manifestations of core concepts of informal inference were identified. Some students demonstrated an understanding of variability across samples, explored uncertainty in the situation, detected trends across samples, and expressed possibilities by generalizing beyond the data. The sequence fosters the early expression of informal inferences and guides instruction that seeks to develop students’ statistical reasoning. © 2025 Mexican Society for Research and Dissemination of Mathematics Education. All rights reserved.