In this article, we describe one possible way to modify volume tasks in textbooks to promote conceptual understanding of the volume formula: length × width × height. From the results of previous studies regarding students' understanding of volume measurement, we identified three conceptual ideas key to understanding volume: filling…

In this study, we examined and compared volume and volume-related lessons in two common core aligned U.S. textbook series and Korean elementary textbooks. Because of the importance of textbooks in the lesson enactment process, examining what textbooks offer to students and teachers is important. Since different parts of a textbook provide…

This study compared area lessons from Korean textbooks and US standards-based textbooks to understand differences and similarities among these textbooks, as well as how these textbooks address known learning challenges in area measurement. Several well-known challenges have been identified in previous studies, such as covering, array structure,…

In this study, we examined five limit lessons using Mathematical Tasks Framework to understand students' opportunities to learn cognitively challenging tasks and maintain cognitive demand during limit lessons. Our analysis of Dr A's five lessons shows that students rarely had opportunities to maintain or increase cognitive demand. There are two…

In this study, we examined 10 integral lessons to understand students' opportunities to learn cognitively challenging tasks and maintain cognitive demand during integral lessons. Our findings reveal issues with implemented tasks as well as the way these tasks were presented to students. We also examined mathematicians' reasons behind their…