How learners understand content is interwoven with the practices in which they engage. Classroom experiences of how students engage with mathematical ideas and problems shape the mathematics that is learned (Boaler, 2002; Franke, Kazemi, & Battey, 2007), affecting the mathematical learning opportunities and the ways in which learners may view the subject and their own knowledge and capability. Consequently, teaching mathematics necessitates attention and sensitivity both to content and to students, and it involves managing dilemmas while maintaining productive relationships (Lampert, 2001; Potari & Jaworski, 2002; Brodie, 2010). For novice teachers navigating multiple demands and expectations, the period of teacher induction (the first years of a teaching career) marks a unique time of teacher learning, when new teachers try, take up, modify, and discard instructional practices, based on perceived effectiveness. The induction years are a time of rehearsal, formation, and evolution of teaching practice. This dissertation presents a close study of instruction over time to illuminate the ways that normative practices may shape mathematical learning opportunities and signal messages about mathematics. The study examined the instructional practice of six novice middle school mathematics teachers teaching in a district with multiple ongoing initiatives to support mathematics instruction with an emphasis on rich tasks and discourse and new teachers’ learning. Applying an instrumental case study approach, the study used observation and interview data, analyzed with a grounded theory approach, to answer the research questions. The analysis illuminated multiple strands of normative practices that, when interwoven, composed instruction and shaped mathematical learning opportunities in either capped or promising ways. Over time these patterns tended to take hold, with certain practices amplified, supported by both contextual and individual factors. In attending to the nature and qualities of instruction of novice teachers in the induction years, the study bridges math education and teacher education to provide insights into how teachers’ actions shape what it means to do math in classrooms, what those actions signal about the discipline and what it means to know math, and what opportunities exist to support teacher capacity around teaching mathematics in a connected and relevant way.