Number facts performance in children with learning disabilities: Examination of a two-factor theory

The purpose of this study was to investigate a two-factor theory of learning disabilities in mathematics, exploring the common finding that children with learning disabilities in math often have difficulty mastering the basic number facts. The theory being investigated in this study was that there are two possible factors contributing to this difficulty. One is impaired phonological processing; the second is a weak sense of number, i.e., a poor understanding of the meanings of and interrelationships between numbers.; Three groups of third grade public school students were studied: (a) those with math disabilities alone, (b) those with concomitant math and reading disabilities, and (c) a contrast group. The purposes of the study were to assess whether the phonological processing skills of the groups of children differed, to assess whether measures of the number sense of the groups of children differed, and to assess whether children with MD/RD have greater difficulty learning the basic number facts than do children with math disabilities alone. It was postulated that there would be differences between the groups of participants on these three factors, with children with MD/RD having the lowest scores on measures of phonological processing, number sense, and math facts mastery. These hypothesized findings were supported in the study.; A timed addition facts assessment was administered to 318 children in six public schools to achieve a norming sample for performance which would aid in the formation of experimental groups. Children comprising the MD-only group were those who were certified with a learning disability or language impairment, and who scored 213 or more of a standard deviation below the norm on the facts assessment. Their performance on a measure of word reading efficiency was above the 25th percentile. The MD/RD group was comprised of students similarly certified and suppressed in their math facts performance, but who also scored at the 25th percentile or below on the word reading efficiency test. Contrast group students were those who had no certified disability and who demonstrated automaticity in recalling the basic addition facts. All participants were assessed on a measure of phonological processing and a measure of number sense, as well as math facts performance. Findings indicated that children with both phonological processing and number sense weaknesses have greater difficulty mastering the basic number facts. This supports the two-factor theory being postulated. One explanation for these findings is that children with MD and RD, who have weaknesses both in phonological processing and in their understanding of number, have no strong channel through which to learn the facts. Students with MD alone are able to use their phonological processing skills to compensate for observed weaknesses in number sense.