Rational numbers are represented by multiple notations: fractions, decimals, and percentages. Whereas previous studies have investigated affordances of these notations for representing different types of information (DeWolf et al., 2015; Tian et al., 2020), the present study investigated their affordances for solving different types of arithmetic…

Lesson study, especially when conducted with support from targeted resources, is often identified as a potentially effective means to support teacher learning. In this study, 80 school-based teams of educators, representing 80 classrooms of third- or fourth-grade students in the US, were randomly assigned to one of four conditions: lesson study…

Three rational number notations--fractions, decimals, and percentages--have existed in their modern forms for over 300 years, suggesting that each notation serves a distinct function. However, it is unclear what these functions are and how people choose which notation to use in a given situation. In the present article, we propose quantification…

To explain children's difficulties learning fraction arithmetic, Braithwaite et al. (2017) proposed FARRA, a theory of fraction arithmetic implemented as a computational model. The present study tested predictions of the theory in a new domain, decimal arithmetic, and investigated children's use of conceptual knowledge in that domain. Sixth and…

When designing professional development for math teachers, teacher confidence, math anxiety, and student performance are factors to consider. St. Lucie Public Schools in Florida has seen a decline in performance in fifth-grade mathematics, where students are first asked to showcase their knowledge on operations for fractions. As a curriculum…

Understanding fractions is critical to mathematical development, yet many children struggle with fractions even after years of instruction. Fraction arithmetic is particularly challenging. The present study employed a computational model of fraction arithmetic learning, FARRA (Fraction Arithmetic Reflects Rules and Associations; Braithwaite, Pyke,…

Mathematics teacher professional-development (PD) programs based on Cognitively Guided Instruction (CGI) have been developed and implemented with tens of thousands of elementary mathematics teachers worldwide since the 1980s. Starting with a focus on addition and subtraction on whole numbers in the first CGI PD program, the content of these…

The Early Fractions Test is a paper-pencil test designed to measure mathematics achievement of third- and fourth-grade students in the domain of fractions. The purpose, or intended use, of the Early Fractions Test is to serve as a student pretest covariate and a test of baseline equivalence in the larger study. In this report, we discuss our…

This report provides a description of the development process, field testing, and psychometric properties of the fall 2015 grades 3-5 Elementary Mathematics Student Assessment (EMSA), a student mathematics test designed to be administered in a whole-group setting to students in grades 3, 4, and 5. The test was administered to 2,614 participating…

Contemporary state math standards emphasize that students must demonstrate an understanding of the mathematical ideas underlying the computations that have typically been the core of the elementary school math curriculum. The standards have put an increased emphasis on the study of fractions in upper elementary grades, which are the years during…

This teacher's guide and student guide are designed to accompany a general mathematics textbook that contains supplemental readings, activities, and methods adapted for secondary students who have disabilities and other students with diverse learning needs. The materials are designed to help these students succeed in regular education content…