Boris Koichu is an Associate Professor at the Department of Science Teaching of the Weizmann Institute of Science. His research interests are in the area of mathematical problem solving and problem posing, from middle school to university. Part of his research focuses on exploring mechanisms of collaborative problem solving in choice-affluent learning environments, such as a dialogical classroom or an online forum. Another part of his research is devoted to implementability of mathematics education research on problem solving and problem posing, by means of creating long-term co-learning partnerships between mathematics teachers and mathematics education researchers. Rina Zazkis Rina Zazkis is a Professor at Simon Fraser University in the Faculty of Education and an Associate Member in the Department of Mathematics. Her research interests are in mathematics education at the undergraduate level and teacher education, focusing on the uses ofmathematical knowledge in teaching. She conducted extensive research on teaching and learning of elementary Number Theory.  She is interested in storytelling and dialogic approaches in teaching and research. In 2016 Zazkis was appointed as Tier 1 Canada Research Chair, a prestigious recognition for excellence in research and research training.