This papers comments on the contributions of "ZDM Mathematics Education" dedicated to the theme "Perception, interpretation and decision making: understanding the missing link between competence and performance". The papers within this issue are brought together under the perspective of the stated aims of this issue, and then…

This paper comments on the theoretical formulations and usage of the construct of teacher noticing in a selection of the papers in this special issue of "ZDM Mathematics Education." The analysis of how the notion of teacher noticing is used in the papers suggests that it draws attention to several interdependencies involved that have not…

Originating in Asia, lesson study is gradually spreading around the globe. As evident from the papers in this issue, we have much to learn as it is implemented in a variety of cultural contexts. In this article we reflect on the goals of lesson study, the organizational supports required to sustain the practice in various contexts, and the…

In this study, the systematic use of variation and invariance in the teaching of mathematics is examined in accordance with two different but compatible explicit frameworks. We consider the following: (1) differences in tasks that follow on from each other can significantly change what can be learned; (2) Chinese teachers (and probably those in…

This article presents a theoretical model of lesson study's impact on instruction, through intervening impact on teachers' knowledge, beliefs and dispositions, teachers' learning community, and curriculum. It also describes four different types of lesson study in Japan, pointing out their synergies in producing a system where local teachers…

This paper discusses how implementation of Lesson Study (LS) has brought about evolving changes in the quality of mathematics classroom teaching in one Chinese primary school. The Japanese model of LS was adapted as a teacher professional development to improve mathematics teachers' teaching practices. The LS group consisted of five mathematics…

There is no doubt that a lesson plan is a necessary product of Lesson Study. However, the collaborative work among teachers that goes into creating that lesson plan is largely under-appreciated by non-Japanese adopters of Lesson Study, possibly because the effort involved is invisible to outsiders, with our attention going to its most visible…

Given the effect of lesson study on improving the quality of mathematics instruction and supporting teachers' professional development, this paper describes how a lesson study using five practices for mathematics discussion was implemented in the Korean context. This paper then analyzes how the lessons were changed through the lesson study cycle…

This study examines how mathematics teaching research specialists mentor practicing teachers during post-lesson debriefs of a lesson study in China. Based on a systematic, fine-grained analysis of 107 h of videotaped mentoring meetings of 20 groups of teachers and teaching research specialists from different elementary schools, this study reveals…

Lesson Study is rapidly becoming one of the most adopted models of teacher professional development worldwide. In this paper, we examine the teachers' discussions that are an integral part of the Lesson Study research cycle. In particular, we investigate the "dialogic mechanisms" that enable teachers' pedagogical intentions to be…

In an effort to increase our understanding of what mathematics young children are capable of when provided with playful yet purposeful opportunities to learn, Canadian researchers initiated lesson study over 4 years with teams of teachers of young children (ages 4-7). The lesson study process followed a lesson study cycle of goal setting,…

Lesson study (LS) has been practiced in China as an effective way to advance teachers' professional development for decades. This study explores how LS improves teaching that promotes students' understanding. A LS group including didacticians (practice-based teaching research specialist and University-based mathematics educators) and mathematics…

This issue of "ZDM" collects research works sharing a common reference to the theoretical framework of Mathematical Working Spaces (MWS), a construction which emerged about one decade ago, and has progressively found its way in the mathematics education community, thanks to the collaborative work of an international group of researchers.…

This article is a commentary on the mathematical working space (MWS) approach and draws on the articles contained in this "ZDM" issue. The article is divided into three parts. In the first part I discuss the place of the MWS approach among the French theories of didactique des mathématiques. In the second part I outline what I think are…

This paper presents an experiment that attempts to mobilise an arithmetic-algebraic way of thinking in order to articulate between arithmetic thinking and the early algebraic thinking, which is considered a prelude to algebraic thinking. In the process of building this latter way of thinking, researchers analysed pupils' spontaneous production…