Què és més rodó? Authors Miquel Albertí Palmer Abstract From a constructivist viewpoint of learning, definitions and theorems are not the beginning but the end of a process that mathematics students should experience in order to build their own learning. Bymeans of several experiences in a first year secondary education classroom,we show how the definitions of circle and degree of roundness are created. Both definitions are used to find out which of the following is rounder, a quail egg or a chicken egg. Under the guidance of the teacher, the social interactionwith classmates and successive approximations of examples and counterexamples, students are able to specify and create both the definition of circle and the degree of roundness. Thework finisheswith an analysis of the didactic implications of the process with respect to future secondary education courses. Downloads Download data is not yet available. Downloads Text complet (Català) Published 2016-06-22 Issue No. 38: juny 2016 Section Articles License The intellectual property of articles belongs to the respective authors.On submitting articles for publication to the journal NouBiaix, authors accept the following terms:Authors assign to Societat Catalana de Matemàtiques (a subsidiary of Institut d’Estudis Catalans) the rights of reproduction, communication to the public and distribution of the articles submitted for publication to NouBiaix.Authors answer to Societat Catalana de Matemàtiques for the authorship and originality of submitted articles.Authors are responsible for obtaining permission for the reproduction of all graphic material included in articles.Societat Catalana de Matemàtiques declines all liability for the possible infringement of intellectual property rights by authors.The contents published in the journal, unless otherwise stated in the text or in the graphic material, are subject to a Creative Commons Attribution-NonCommercial-NoDerivs (by-nc-nd) 3.0 Spain licence, the complete text of which may be found at https://creativecommons.org/licenses/by-nc-nd/3.0/es/deed.en. Consequently, the general public is authorised to reproduce, distribute and communicate the work, provided that its authorship and the body publishing it are acknowledged, and that no commercial use and no derivative works are made of it.NouBiaix is not responsible for the ideas and opinions expressed by the authors of the published articles.