Ní Shúilleabháin, AoibhinnAoibhinnNí Shúilleabháin2016-07-252016-07-252015 the A2015-02-08http://hdl.handle.net/10197/7789Ninth Congress of the European Society for Research in Mathematics Education (CERME 9), Prague, Czech Republic, 4-8 February 2015This research presents features of knowledge of content and students (KCS) and knowledge of content and teaching (KCT) as empirical evidence of mathematics teachers' pedagogical content knowledge (PCK) utilised and enhanced through their participation in iterative cyclesof lesson study. Over the course of one academic year, twelve teachers in two secondary schools engaged in this research as a double case study of teacher learning within a lesson study community. Qualitative data was generated through audio recordings of teacher meetings and through multiple teacher interviews. Dialogue within the lesson study communities was mapped to a framework of PCK as proposed by Ball, Thames and Phelps (2008). Results of this study find empirical evidence ofthe features of KCS and KCT in teachers' planning and reflection conversations and demonstrate teacher learning over iterative cycles of lesson study.enLesson studyPedagogical content knowledgeMathematics educationConference Publication273427402016-03-22https://creativecommons.org/licenses/by-nc-nd/3.0/ie/