Vol. 37 Num. 2 (2017) - front cover0 Marie Therese Farrugia On semiotics and jumping frogs: the role of gesture in the teaching of subtraction ABSTRACT 2 Jason Cooper ,  Alon Pinto Mathematical and pedagogical perspectives on warranting: approximating the root of 18 ABSTRACT MORE INFORMATION   8 Ernest Kofi Davis Communication: A three-tier teaching model for teaching mathematics in context ABSTRACT 14 From the archives Communication: From the archives15 Vince Geiger ,  Claire Margolinas ,  Rudolf Sträßer Communication: On the challenges of multi-linguisme in mathematics education research ABSTRACT 16 Alayne Armstrong Bricolage in middle years school mathematics ABSTRACT 19 Geneviève Barabé ,  Jérôme Proulx Révolutionner l’enseignement des mathématiques : le projet visionnaire de Seymour Papert ABSTRACT 25 Caroline Yoon The writing mathematician ABSTRACT 30 Linda Marie Ahl ,  Tuula Koljonen ,  Ola Helenius The voice of curriculum developers in teacher guides ABSTRACT 35 - Contributor affiliations and contact information40