The purpose of this study was to examine patterns in fourth-grade teachers' use of instructional moves in the implementation of standards-based mathematical teaching practices. Using a mixed methods sequential explanatory design, the study consisted of two phases: quantitative selection and qualitative analysis. The first phase of the study utilized quantitative analyses of CLASS (Classroom Assessment Scoring System; Pianta et al., 2008) scores and Mathematics Scan (M-Scan, Berry et al., 2010) scores to select participants who exhibit strengths in general teaching quality as measured by CLASS, and a range in strengths of the implementation of standards based mathematical teaching practices. Ten teachers were selected from a sample of 84 fourth grade teachers from the Responsive Classroom Efficacy Study (RCES) (Rimm-Kaufman, Fan, & Berry, 2007). Five of these teachers rated in the top quartile on both CLASS and M-Scan, while the other five rated in the top quartile of CLASS, but the lowest quartile of M-Scan scores. Based on this selection of participants, teachers' videotaped mathematics lessons (3 per teacher) were analyzed to determine similarities and differences in the instructional moves used within each subgroup. These similarities and differences were then compared between the two groups to compare and contrast the use of instructional moves. Several key differences in instructional practices were found: the use of assessments for feedback (real-time versus a time lapsed feedback loop), the focus on procedural versus conceptual processes, and skills based teaching versus teaching for understanding. Several other instructional moves were named in this study, including but not limited to: student directed discourse, sequencing and timing of the lesson, and purposeful error use. The findings of this study help to further delineate a clearer picture of facets of instruction related to the implementation of standards-based mathematical teaching practices. This can be influential for pre-service teachers as well as in-service teachers and leaders of professional development in highlighting specific instructional moves to utilize in fostering high quality standards-based mathematical teaching practices. [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.]