Geometry

This study examines technology-enhanced teacher responses and students’ written mathematical explanations to understand how to support effective teacher responding and the centering of students’ mathematical ideas. Although prior research has focused on teacher noticing and responding to students’ mathematical ideas, few studies have explored the revisions that students make to their written explanations after teacher responding and very few explore this in authentic classroom contexts.

This study examines technology-enhanced teacher responses and students’ written mathematical explanations to understand how to support effective teacher responding and the centering of students’ mathematical ideas. Although prior research has focused on teacher noticing and responding to students’ mathematical ideas, few studies have explored the revisions that students make to their written explanations after teacher responding and very few explore this in authentic classroom contexts.

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.

In this collection of materials, four geometric topics are covered in animated, digital materials.

This peer-reviewed research journal publication addresses one of the grant goals with respect to how students performed on a set of proof tasks. Student work was documented through the use of smartpen technology which allowed the researchers to "track" students' written work on the proof tasks as well as hear the students' explanations of their thinking about the tasks. Although the two tasks highlighted in this paper were relatively routine triangle congruent proofs, only 7 out of 23 of the sampled students were successful on both proofs.

Students who earned high marks during the proof semester of a geometry course were interviewed to understand what high-achieving students actually took away from the treatment of proof in geometry. The findings suggest that students had turned proving into a rote task, whereby they expected to mark a diagram and prove two triangles congruent.

Presentation slides and handout from the 2019 NCTM Regional Conference in Nashville, TN.

Linear Algebra and Geometry is organized around carefully sequenced problems that help students build both the tools and the habits that provide a solid basis for further study in mathematics. Requiring only high school algebra, it uses elementary geometry to build the beautiful edifice of results and methods that make linear algebra such an important field. 

Cirillo, M. & Hummer, J. (2019). Addressing misconceptions in secondary geometry proof. Mathematics Teacher, 112(6).