Approximately 5 to 7% of school-age students have a learning disability related to mathematics (Shalev, Auerbach, Manor, & Gross-Tsur, 2000), but the percentage of students who experience mathematics difficulty is much greater. For example, results from the 2015 National Assessment of Educational Progress (NAEP; National Center for Education Statistics, 2015) indicate 60% of fourth-grade students and 67% of eighth-grade student performed at or below a basic level of proficiency in mathematics. For students with disabilities, the percentage of students below a basic level of performance in mathematics was even greater, with 80% of fourth-grade students at or below basic levels of proficiency and 92% of eighth-grade students at or below basic, indicating lack of proficiency in mathematics. Yet, research documents that effective instruction can reduce the likelihood that a student will be identified as having a mathematics difficulty or disability (MD; e.g., Compton, Fuchs, Paulsen, Bryant, & Hamlett, 2005). [This study was published in "Learning Disabilities Research and Practice" v31 n3 p130-141 Aug 2016 (EJ1108480)].