Abstract
Early mathematical skills predict later mathematical skills and general school achievement. The approximate number system (ANS), number line estimation, and working memory (WM) were found to be important predictors of the development of mathematical skills. However, studies specifying contributions of ANS, number line estimation, and WM at developmental levels are scarce. Therefore, the current study aimed to evaluate differential contributions of ANS, number line estimation, and WM to mathematical skills in preschool and primary school children. German preschool (N = 68, M = 6 years) and primary school children (N = 66, M = 9 years 1 month) completed an age-appropriate test for mathematical skills, a non-symbolic comparison task, a number line estimation task, WM span tasks, and a nonverbal intelligence task. Results indicated that ANS accuracy, number line estimation performance, and WM capacity were significant predictors for mathematical skills in both groups when controlled for influences of sex and nonverbal intelligence. Importantly, we also observed that only number line estimation performance contributed differentially to mathematical skills as it was a significantly stronger predictor in primary school children as compared to preschool children. In sum, these results suggest that the start of formal instruction on symbolic numerical representations in primary school is reflected in the contribution of related task performance to overall mathematics. To extend current findings, future studies may focus on differentiating age groups in a more fine-grained way to evaluate developmental trajectories of specific contributions of cognitive variables.