While previous work in the domain of proportional reasoning has primarily focused on the coordination of integer quantities, this study investigates how students coordinate fractional quantities. Fine-grained analysis of two seventh graders' responses to a set of systematically designed proportional tasks, shows how their knowledge of multiplication and division from the domain of integers affords them the necessary resources to coordinate the fractional quantities. Further, it succinctly shows how the numeric feature of the fractional quantities cues and constrains them.