Using a qualitative case study approach, this research explored the perceptions of middle school students on the role of their mathematics teacher in their success or failure to achieve in his mathematics classroom. Also, the study examined the teacher's perceptions of his role in the students' achievement. Further, the research explored the teacher's strategies while teaching Algebra I. Through the use of 135 hours of classroom observations, student interviews, teacher interviews, and field notes, the following teacher strategies were supported: the use of routine, extensive modeling, scaffolding, differentiation, real life examples, and strong encouragement. Achievement data and end-of-course assessments confirmed that this low-performing, high-poverty middle school had 100% pass rates on the state Algebra I end of course test. [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.]