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Insights into Math Learning Difficulties

The innate ability to estimate quantities is impaired in children who have a math learning disability, according to a new report. The study also found that those who do poorly in math but aren’t considered learning disabled struggle with math for different reasons.

People with math learning disability, also known as dyscalculia, have difficulty understanding math concepts and solving even simple math problems despite adequate education. About 10% of school-age children have persistent and significant difficulties with math, while many more fail to reach basic levels of mathematics achievement. The causes of dyscalculia, however, remain poorly understood.

To learn more, researchers decided to explore the relationship between children’s mathematics achievement and their innate ability to estimate and compare quantities without counting. This capability, referred to as the approximate number system (ANS), is normally present in infants and improves with age. We rely on ANS skills in daily life, such as when we estimate which line will move more quickly at the grocery store.

The researchers gave 71 ninth graders 2 series of tests designed to measure their ANS skills. For the first series, the children viewed groups of dots and were asked to say whether there were more blue or yellow dots. In the second, 9 to 15 dots of one color appeared, and the children were asked how many dots they saw. Each screen was visible for only a fraction of a second, so the children didn't have time to count the dots. Each series of tests consisted of dozens of screens.

The students’ math abilities had been tested at regular intervals since kindergarten. The scientists classified the children into 4 groups based on these math achievement scores: high achieving (above the 95th percentile), typically achieving (25th to 95th percentile), low achieving (11th to 25th percentile) and math learning disabled (10th percentile and below). The research was conducted by Dr. Michèle Mazzocco at the Kennedy Krieger Institute and Johns Hopkins University and her colleagues Drs. Lisa Feigenson and Justin Halberda of Johns Hopkins University. It was funded in part by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).

In the advanced online edition of Child Development on June 16, 2011, the researchers reported that math learning disabled students had the poorest ANS scores. This finding suggests that problems with the ANS may underlie math difficulties for children in this group. However, low-achieving children were no more likely to have poor ANS scores than children in the higher achieving groups. Math difficulties in low-achieving children, then, likely stem from a cause or causes distinct from the ANS.

“Children with mathematical learning difficulties are often viewed as a uniform group of students, for whom a single type of special instruction or math curriculum is appropriate,” Mazzocco says. “Our findings suggest, however, that children have difficulty with math for different reasons.”

Research to identify these reasons may now lead to new ways of identifying children at risk and tailoring teaching methods to help them.