The perception of what a teacher says s/he does in the classroom may or may not match the reality of their actual teaching practice. This case study considers one second-grade teacher's instructional methods and pedagogical decisions when teaching number sense and her perception of what informed her teaching practice. This teacher supported students' development of mathematical strategies, valued debriefing time, and students' sharing mathematical strategies. Additionally, she listened to students purposely by probing their thinking. Her experience in a mathematics professional development program helped her be consistent in her beliefs about mathematics learning, her perception of her teaching, and the observed practice.