Background: This study considers the moment-bymoment mathematics discourse of teachers and students and the relationship of these discourses to student learning. I focus on the discursive constructs of responsiveness to students' mathematical thinking and the intellectual work in teacher and student discourse. Responsiveness to students' mathematical thinking is the extent to which one acknowledges, elicits, takes up, or builds on student thinking in-themoment. Intellectual work reflects the cognitive work set in motion or performed by a speaker within a given turn of talk. Methods: I developed analytic frameworks that accounted for different levels of responsiveness and intellectual work during whole-class instruction in seventh-grade mathematics classrooms. These frameworks captured variation in responsiveness and intellectual work which was linked to student achievement using MLM. Findings: Analyses revealed a significant positive relationship between teachers' responsiveness to student thinking and student learning. Additionally, the intellectual work requested by the teacher was related to the level of intellectual work students provided, acting as an upper bound on students' mathematical activity. Contributions: The analytic frameworks developed for this study identified forms of responsiveness (High Exploring moves) that were most effective for student learning and specified the relationship between a teacher's and her students' levels of intellectual work.