The contributions of domain-general abilities and domain-specific knowledge to subsequent mathematics achievement were longitudinally assessed (n = 167) through 8th grade. First grade intelligence and working memory and prior grade reading achievement indexed domain-general effects, and domain-specific effects were indexed by prior grade…

Solutions to addition and subtraction word problems were studied in a three-year longitudinal study that followed 88 children from grades one to three. They solved problems using a variety of strategies before formal instruction and used invented strategies several years after formal instruction. Four levels of problem-solving ability were found.…

Over a 10-month period, normal children showed an increased reliance on memory retrieval and a decreased reliance on counting when they solved addition problems. There was an increase in speed of counting and of retrieving addition facts from long-term memory. Children with a mathematical learning disability showed no change in problem-solving…