Abstract
Many students struggle to master the concept of two-digit subtraction as a result of lacking appropriate content vocabulary and developing a solid understanding of base-ten procedures. The researcher conducted a qualitative study to investigate the effectiveness of integrating concrete and abstract models of mathematical concepts to explore the ways in which students are better able to solve subtraction problems and explain their thinking. Twenty-four second grade students from a suburban school in Northern California were invited to participate in this four-week study. Ultimately, five students were selected as a representation of the whole group of participants for the purposes of more in-depth examination. An initial interview and a post interview were conducted to analyze and examine the growth of student understanding of subtraction as a result of the integration of the concrete models. The discussion of results outlines key recommendations for planning and implementing effective instruction in subtraction.