Contrasting Cases in Geometry: Think Alouds with Students about Transformations

There is strong empirical evidence in support of learning from comparisons in mathematics education research (Rittle-Johnson & Star, 2007; Star, Pollack, et al., 2015; Star et al., 2016). Comparisons have produced gains in students’ procedural knowledge, flexibility, and conceptual knowledge of algebra (Lynch & Star, 2014; Star, Newton, et al., 2015; Star, Pollack, et al., 2015). The Animated Contrasting Cases in Geometry project seeks to extend this research and transform the learning of geometry for middle school students by designing a supplementary digital animated curriculum. The curriculum materials for each lesson are organized into Worked Example Pairs (WEPs), which include five unique features: a page for the first student’s solution strategy on a given geometry task, a page for the second student’s solution to a geometry task (which could be the same or different task as was shown on first student’s page), a page with both students’ strategies side-by-side, a discussion sheet with four questions for the students to answer, and a thought bubble page summarizing the key mathematical concepts in the problem. The discussion sheet and thought bubble page are designed to make the instructional goal of each WEP more explicit and to scaffold discussions among students as they summarize their work from the WEPs (Star, Pollack, et al., 2015). This paper focuses on the Transformations unit, which is one of four units.

Krupa, E. E., Bentley, B., & Mannix, J. P. (2021). Contrasting cases in geometry: Think alouds with students about transformations. Proceedings from the 43rd Annual Conference of the North American Chapter of the International Group for the Psychology of Mathematics Education, Philadelphia, PA.