<![CDATA[Effective mathematics learning requires well-structured resources that support students’ conceptual understanding. Mathematics textbooks play a crucial role in organizing mathematical knowledge; however, how textbook tasks structure epistemic pathways for introducing the concept of sphere volume across different educational contexts remains underexplored. This study examines the epistemic structures of tasks related to the early concept of sphere volume in middle school mathematics textbooks from Australia, Indonesia, and Canada using a multi-theoretical qualitative comparative framework. These countries were selected to represent different educational and curricular contexts, enabling a comparison of how textbook tasks and epistemic pathways are organized across contexts. The trustworthiness of the analysis was ensured through theoretical triangulation across the analytical frameworks and inter-rater discussions to establish consistency and coherence in data interpretation. The results revealed substantial variations in the organization of tasks and techniques across the three textbooks, reflecting differences in epistemic orientations and levels of cognitive demand. Specifically, five types of tasks were identified in the Australian textbook, three in the Indonesian textbook, and nine in the Canadian textbook. These types of tasks formed distinct sequences with varying cognitive demands, and some task sequences indicated potential textbook-induced learning obstacles. These findings highlight differences in the epistemic organization of sphere volume tasks and provide insights for designing more coherent task sequences aligned with students’ cognitive processes.]]>
