Working memory and domain-specific precursors predicting success in learning written subtraction problems

This study was designed to identify individual differences predicting competence in solving written subtractions with borrowing in second-grade schoolchildren. To examine the role of domain-general and domain-specific precursors, a group of 68 second-graders was tested at three different sessions. Domain-general precursors were analyzed during the first session, including four working memory (WM) tasks, distinguishing between simple-storage and complex-span WM tasks. The domain-specific mathematical abilities tested were knowledge of symbols, arithmetical fact retrieval, understanding of the positional value of digits, and alignment skills. During the second and third sessions, children were taught written subtraction algorithms, first without and then with borrowing procedures, and were then immediately assessed on their acquired competences. Path analysis models were run and the final model showed that performance in written subtractions with borrowing was predicted by both visuospatial WM and specific mathematical skills. The results are discussed for their theoretical and educational implications.