A Steiner chain is defined as the sequence of n circles that are all tangent to two given non-intersecting circles. A closed chain, in particular, is one in which every circle in the sequence is tangent to the previous and next circles of the chain. In a closed Steiner chain the first and the "n"th circles of the chain are also tangent…

The aim of this study was to investigate the effect of using dynamic geometry software (GeoGebra) on the eighth-grade students' conceptual understanding and the retention of learning regarding linear equations and slope. In this study, a quasi-experimental design with pre-test, post-test and delayed post-test was employed. This study was conducted…

The regular pentagon had a symbolic meaning in the Pythagorean and Platonic philosophies and a subsequent important role in Western thought, appearing also in arts and architecture. A property of regular pentagons, which was probably discovered by the Pythagoreans, is that the ratio between the diagonal and the side of these pentagons is equal to…

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…

Despite the benefits of teaching computational thinking (CT) and applying coding tools in schools, many teachers feel unprepared to use these technologies. Hence, we introduced CT concepts and coding tools to pre-service teachers (n=36; 17 in online class and 19 in in-person class), equipping them with digital competencies through activities with…

This study investigated the cognitive and social processes through which high school students acquire the differential concepts through communication in a dynamic geometry environment through some cases. Additionally, we observed how a dynamic geometry environment affects these processes. To achieve this objective, eight students were recruited by…

This report documents how one undergraduate student used set-based reasoning to reinvent logical principles related to conditional statements and their proofs. This learning occurred in a teaching experiment intended to foster abstraction of these logical relationships by comparing the predicate and inference structures among various proofs (in…

Our article aims to show how illuminating mathematical work as a concept from didactics of mathematics is useful in understanding issues relating to proving and learning of proof, with or without technology. After posing our hypotheses on the relationship of proof with mathematical work, the pedagogical intent of historical elements of geometry…

In fall 2013 the author taught a graduate course entitled Topics in Geometry for Middle and High School Teachers. The majority of the participants had extensive experience teaching mathematics in middle school or high school. The fact that participants were rather comfortable with the basic concepts of school geometry made it both possible and…

This study examined what factors might have a positive impact on students' learning outcomes in mathematical understanding and computational thinking skills. Specifically, whether the proposed instructional design combining computational perspectives and an embodied approach in mathematics learning improves (a) mathematics learning, (b)…

Graphing function is an important issue in mathematics education due to its use in various areas of mathematics and its potential roles for students to enhance learning mathematics. The use of some graphing software assists students' learning during graphing functions. However, the display of graphs of functions that students sketched by hand may…

The aim of this study is to examine the effect of Brain Based Learning on second grade junior high school students? conceptual understanding on polyhedron. This study was conducted by using post-test only control group quasi-experimental design. The subjects of this study were 148 students that divided into three classes. Two classes were taken as…

The Odd Shape Out task was an open-ended problem that engaged students in comparing shapes based on their properties. Four teachers submitted the work of 116 students from across the country. This article compares various student's responses to the task. The problem allowed for differentiation, as shown by the many different ways that students…

The aim of the study is to conceptualize the technology-aided mathematical modelling process in the frame of cognitive modelling perspective. The grounded theory approach was adopted in the study. The research was conducted with seven groups consisting of nineteen prospective mathematics teachers. The data were collected from the video records of…

A teacher-centered, examination-driven instructional approach emphasizing knowledge of facts and standard methods through drill-and-practice without use of Information and Communications Technology (ICT) is still dominant in Nepalese high schools. In this article, we present a classroom study in which the traditional instructional approach has…