Pre-service teachers (PSTs) often encounter challenges grasping the conceptual understanding of fractions, which can affect their readiness to teach this topic. This study investigates a novel approach to enhancing PSTs' comprehension of fractions by focusing on the fraction-as-a-measure meaning within a measurement context. Through a modified teaching experiment utilizing hypothetical learning trajectories, this research explores the progression of one PST, Nina, and her understanding of fraction concepts. Specifically, it examines the effectiveness of instructional task sequences in promoting conceptual understanding and addressing challenges and difficulties in fraction concepts and reverse reasoning. Results reveal Nina's transitions in understanding fraction concepts through task sequences, with a focus on three sequences: Generating Quantities Using Partitioning and Iterating, Comparing Fractions, and Recursive Partitioning. Findings illustrate PSTs' challenges and the need for carefully engineered instructional support. Integration of a measurement context and the "Fraction Bars" application proves beneficial in enhancing PSTs' conceptual understanding and reasoning skills. Further research is recommended to explore the sustained impacts of such instructional interventions on PSTs' conceptual development and variations in task sequences across diverse student populations.