The present study examined the developmental change in number and length acuities and their respective relationship with achievement in various domains of mathematics in second vs. fourth graders. Length acuity was measured with a comparison task, in which participants were asked to choose the longer between a pair of lines. Number acuity was…

This article proposes an integrated theory of acquisition of knowledge about whole numbers and fractions. Although whole numbers and fractions differ in many ways that influence their development, an important commonality is the centrality of knowledge of numerical magnitudes in overall understanding. The present findings with 11- and 13-year-olds…

We examined developmental and individual differences in 6th and 8th graders' fraction arithmetic and overall mathematics achievement and related them to differences in understanding of fraction magnitudes, whole number division, executive functioning, and metacognitive judgments within a crosssectional design. Results indicated that the difference…

The Skill Acquisition Measures (SAM) were designed by the Lancaster (Pennsylvania) School District as criterion referenced tests for mathematics. This manual consists of copies of the student test forms for level 2, with additional information for the teacher's use. Each of the test items is presented with the correct answers and the criteria for…

To help classroom teachers construct mathematics tests, nineteen general objectives, corresponding sub-objectives, sample test items, and answers are presented. In general, sub-objectives are arranged in increasing order of difficulty. The objectives were written to comprehensively cover three categories: (1) set theory; (2) numeration (Roman,…