In their Research Commentary, Kitchen and Berk (2016) argue that educational technology may focus only on skills for low-income students and students of color, further limiting their opportunities to learn mathematical reasoning, and thus pose a challenge to realizing standards-based reforms. Although we share the concern about equity and about…

In this study, we investigated how Grade 3 and 4 students' organizational structure for volume units develops through repeated experiences with a virtual manipulative for building prisms. Our data consist of taped clinical interviews within a micro-genetic experiment. We report on student strategy development using a virtual manipulative for…

Although some research-based educational practices have shown promise, many fail to be implemented at a scale that affects more than a small proportion of children. Further, research on interventions for young children includes mixed results, with most documenting "fadeout" of effects after several years, but some showing lasting…

Do young children naturally develop the foundations of science, technology, engineering, and math (STEM)? And if so, should we build on these foundations by using STEM curricula in preschools? In this article, Douglas Clements and Julie Sarama argue that the answer to both these questions is yes. First, the authors show that young children possess…

In this study we investigated eighth grade students' informal justification for the circle area formula to expand accounts of the measurement knowledge for middle-school age students. Data were collected during three paired interviews of a three-year teaching experiment. Here we describe schemes students exhibited as they operated on measurement…