Attention to the pursuit of equity has been a growing priority for mathematics classrooms in the last two and a half decades. While classroom discourse has become a central feature of classrooms that strive toward equity, one continuing concern for classroom researchers in mathematics education involves understanding how and when group interactions support or interfere with student learning. In this dissertation, I respond to these calls by simultaneously offering perspectives of mathematical learning from underrepresented students alongside empirical evidence of these students' transformative classroom experiences. In this study, I used ethnographic methods to analyze student and teacher classroom interactions and interviews during the first and last units in a semester one Algebra 1 class where learning was facilitated primarily by student-led whole class and student-student small-group interactions. In Paper 1, I propose a combined analytic framework for studying classroom interactions by coordinating Status and Positioning Theories. In Paper 2, I investigate the teacher's classroom structures and pedagogical practices to reveal a process for delegating mathematical authority to students. Students' perceptions reveal the classroom structures, and pedagogical practices expand what counts as mathematical smartness in this classroom. In Paper 3, I investigate students' changed perceptions of competence over the course of the study. I find that the development of specific social and sociomathematical norms mediated students' perceptions of improved competence in this classroom. Throughout this dissertation, I argue that this teacher's practice strives toward equity by expanding mathematical smartness and improving students' perceptions of competence in mathematics. I suggest that future work should analyze the systemic inequities that lead to uneven representation of any groupings of students in tracked classrooms. I also argue that future work striving toward equity in mathematics education should further investigate empirical evidence of additional processes for delegating authority to high school students, additional classroom structures and pedagogical practices that expand mathematical smartness, additional social and sociomathematical norms that can positively affect students' perceptions of competence, and additional classrooms that contribute to successes for "all" students in high school mathematics. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]