Abstract
Fractions are an important mathematical concept for both more advanced mathematical concepts and daily living activities (e.g., cooking) and thus are important for all students to learn. In this study, researchers explored the use of the virtual-abstract (VA) instructional sequence to teach three middle school students with disabilities three fraction concepts—equivalent fractions, addition of fractions with unlike denominators, and multiplication of fractions by a whole number. For each student for each fraction concept, a functional relation existed between the intervention (i.e., the VA instructional sequence) and the dependent variable (i.e., accuracy on problems of the fraction concept). The students acquired the fraction concepts, but there were struggles to maintain their performance when no instruction was provided.