"Flatland: A Romance of Many Dimensions" is an 1884 novella written by English schoolmaster Edwin Abbott. He describes what it would be like to live in a two-dimensional (2D) world--Flatland. It is fascinating reading that underscores the challenge of teaching three-dimensional (3D) mathematics using 2D tools. Real-world applications of…

The Common Core State Standards for Mathematical Practice (CCSSI 2010) elevate the ways of thinking used to create mathematical results to the same level of importance as the results themselves. These mathematical habits of mind (MHoM), or "specialized ways of approaching mathematical problems and thinking about mathematical concepts that…

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…

According to the National Center for Education Statistics (2016), the number of public school students in the United States who were English learners (ELs) was estimated at 4.5 million. However, in 2005, the national standardized testing scores (Fry 2007) show that about 51 percent of eighth-grade EL students were behind other students in reading…

Although research shows that Computer Algebra Systems offer pedagogical opportunities, more than a decade later some teachers are reluctant to change established practices. In 2002, the University of Melbourne in Australia launched a research project to investigate implementation of a senior mathematics course in which students could use a…

This article highlights three of the eight Mathematics Teaching Practices (MTP) published in the National Council of Teachers of Mathematics' (NCTM's) "Principles to Actions: Ensuring Mathematical Success for All" (2014): (1) facilitating meaningful mathematical discourse (MTP 4); (2) posing purposeful questions (MTP 5); and (3)…

The American educational landscape is changing rapidly, and so are the students in American mathematics classrooms. In the New York City public schools, one of every four students is an English language learner (ELL) (New York City Department of Education 2014). Mathematics teachers find themselves teaching either in a classroom that contains all…

Principles and Standards for School Mathematics (NCTM 2000) states, "Technology is essential in teaching and learning mathematics; it influences the mathematics that is taught and enhances students' learning." The focus on reasoning and sense making with technology in the lesson presented in this article will enable students to do more…

When teaching mathematics with technology, the author does so in the belief that technology enables students to experience mathematical ideas in a way that might not otherwise be possible. However, teachers must be careful: Sometimes technology does not produce results in the way that they or their students expect. Rather than allowing unexpected…

Twenty-five years of teaching grades 8-12 mathematics has shown the author that students learn best when they can construct their own knowledge (constructivism) and that students, given appropriate guidance, can and will take on responsibility for their own learning (self-regulation theory). This article describes some classroom tools that she has…

The National Council of Teachers of Mathematics (NCTM) launched the "standards-based" education movement in North America in 1989 with the release of "Curriculum and Evaluation Standards for School Mathematics," an unprecedented action to promote systemic improvement in mathematics education. Now, twenty-five years later, the…

Erin has been teaching at Centennial High School for five years. Always an excellent mathematics student, she is nonetheless surprised at the amount of mathematics she has learned since she began teaching. She recently assigned what she thought was a fairly straightforward proportional reasoning task, only to be challenged to understand the…

Many preservice teachers come into teacher education programs with a rule-based view of mathematics, a view that is to a large extent indicative of their previous school experiences. In teaching preservice elementary school teachers, this author has used his instrumental understanding as the starting point for rich discussions about the…

Many students read for pleasure, but how many, stranded in an expansive library, would willingly reach for a mathematics textbook? One reason this scenario is so inconceivable is that mathematics textbooks are organized less as exercises in storytelling and more as how-to manuals. Unfortunately many mathematics teachers instruct accordingly. This…

Although traditional textbooks may not guide students through explorations or encourage group work, as many standards-based curricula do, virtually all textbooks contain mathematically accurate information and problems that, with adjustment, can be leveraged to support mathematical curiosity, reasoning, and discussion. Teachers who recognize rich…