This qualitative research study investigates the ways middle-grades students’ numerical reasoning relates to their solutions to word problems that can be modeled by systems of linear equations. 18 students in grades 6 through 9 participated in task-based semi-structured clinical interviews. Students’ numerical reasoning was assessed using the framework, number sequences, and their problem-solving was observed on two word problems that could be modeled using systems of linear equations. Results show that students’ stages of numerical reasoning were more closely related to their problem-solving strategies than their mathematics instruction. Additionally, students with less sophisticated numerical reasoning commonly used pre-algebraic strategies, whereas students with more sophisticated numerical reasoning more commonly utilized algebraic reasoning strategies. This study contributes a breadth of pre-algebraic strategies that students used to solve word problems that can be modeled by systems of linear equations in relation to their numerical reasoning. Theoretical and instructional implications are also discussed.