"May 2014."Dissertation Supervisor: Dr. Kathryn B. Chval.Includes vita.Underachievement in algebra along lines of race, class, and gender is a striking and pervasive phenomenon in the Colombian educational system. Black and poor students persistently lag behind their mestizo and wealthier peers. Explanations for the low mathematics performance of these student populations are usually grounded in essentialist perspectives that mainly attribute the students' failure to their racial, ethnic, and economic status. Adopting a sociopolitical perspective, the present study investigated the relationships between student social background, teacher expectations, and teaching practices. In particular, the study focuses on the relationships between the forms wherein student social backgrounds nurture and shape teacher expectations and influence the teaching practices implemented to help students build meaning of algebraic objects and procedures. Using a comparative method and an interpretative approach, the expectations and teaching practices of three different mathematics teachers in three different social contexts were studied for four weeks. Their classes were filmed and the students wore sunglass cameras to record their interactions with their peers and teachers. The teachers were also interviewed and debriefed once a week during the observation time. The main findings point out a pronounced relationship between teachers' expectations and the students' backgrounds. The teachers hold cultural and class deficit views about black and poor students and position them as incapable of learning complex and meaningful algebraic knowledge. Such expectations translate into poor teaching practices, practices of exclusion and marginalization within the mathematics classrooms, and low quality interactions between teachers and students that impede the acquisition of important competences needed to successfully participate in the democratic and political life within the Colombian society. Implications for research and teacher education are suggested.Includes bibliographical references (pages 238-259)