"When you hear hoofbeats, look for horses, not zebras." This common saying in medicine (often attributed to Theodore Woodward, MD, of the University of Maryland School of Medicine) advises doctors to stick to the expected or likely diagnosis, rather than anticipating an unusual or atypical one. As a result, uncommon medical diagnoses are…

Recently a team of third- and fourth-grade teachers tested instructional ideas on the topic of division with remainders (DWR) using lesson study. The Common Core State Standards for Mathematics give little attention to the concept of the remainder, specifying only that students are to solve problems for which remainders must be interpreted (NGA…

Spatial ability was defined by Lohman (1996) as the ability to create, maintain, retrieve, and change visual pictures. Linn and Peterson (1985) distinguished among spatial perception, mental rotation, and spatial visualization. Spatial perception is the determination of spatial connections with respect to the orientation of the learners' body;…

Despite holding wide-ranging experiences with constant velocity and non-zero acceleration, students wrestling with physical science concepts struggle to demarcate the two distinct characteristics of motion. In fact, this prior experience and loose familiarity with associated terminology often act as an obstacle toward a deep and robust…

Modeling is an effective tool to help students access mathematical concepts. Finding a math teacher who has not drawn a fraction bar or pie chart on the board would be difficult, as would finding students who have not been asked to draw models and represent numbers in different ways. In this article, the authors will discuss: (1) the properties of…

Do your students think they can model ratios with sets of discrete objects and combine them to show the addition of ratios? Do they believe that equivalent ratios are based on additive relationships rather than multiplicative ones? What tasks can you offer what questions can you ask to determine what your students know or don't know and move them…

When teaching algebra concepts to middle school students, the author often hears questions that echo her own past confusion as a young student learning to write linear equations using data tables that show only input and output values. Students, expected to synthesize the relationship between these values in symbolic representation, grow…

This article presents the Snail problem, a relatively simple challenge about motion that offers engaging extensions involving the notion of infinity. It encourages students in grades 5-9 to connect mathematics learning to logic, history, and philosophy through analyzing the problem, making sense of quantitative relationships, and modeling with…

To help middle school students make better sense of decimals and fraction, the author and an eighth-grade math teacher worked on a 90-minute lesson that focused on representing repeating decimals as fractions. They embedded experimentations and explorations using technology and calculators to help promote students' intuitive and conceptual…

The Common Core State Standards (CCSSI 2010) and NCTM's (2014) "Principles to Actions" agree that "for meaningful learning of mathematics, tools and technology must be indispensable features of the classroom . . . that support students in exploring mathematics as well as in making sense of concepts and procedures and engaging in…

"Low threshold, high ceiling" tasks are accessible to diverse learners; invite a wide range of approaches; and hold the potential to further challenge, strengthen, and extend everyone's mathematical reasoning. In this article, the authors present a family of Brick Pyramid problems as examples of "low threshold, high ceiling"…

The phenomenon of outbreaks of dangerous diseases is both intriguing to students and of mathematical significance, which is exactly why the authors engaged eighth graders in an introductory activity on the growth that occurs as an epidemic spreads. Various contexts can set the stage for such an exploration. Reading adolescent literature like…

By 2020, five of the top ten in-demand jobs in the United States will be in information technology (Moeller 2012). Companies across the nation are seeking a new type of employee: one who is computer savvy and who is familiar with computer coding, data, mathematics, and augmented reality (Leber 2013). Recent reports indicate that, although students…

Hands-on activities are one of the most popular instructional tools that enhance student understandings of the science concepts and enable them to get involved in science practices as well. However, most of science educators underestimate its effectiveness in the classrooms. In order to illustrate how these activities could be utilized for science…

Learning about the area formulas provides many opportunities for students even at the beginning of junior secondary school to experience mathematical deduction. For example, in easy cases, students can put two triangles together to make a rectangle, and so deduce that the area of a triangle is half the area of a corresponding rectangle. They can…