Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal…

Training with a self-instruction strategy was found to be effective in teaching addition and subtraction to 52 educable mentally retarded and learning-disabled children with arithmetic deficits. Sixteen of the children, who were categorized as impulsive, showed a more reflective cognitive style following the training. (Author/JDD)