Domain-specific and domain-general skills as predictors of arithmetic fluency development

We investigated Norwegian children's (n = 262) development in arithmetic fluency from first to third grade. Children's arithmetic fluency was measured at four time points, domain-specific (i.e., symbolic magnitude processing and number sequences) and domain-general skills (i.e., working memory, rapid naming, non-verbal reasoning, and sustained attention) once in the first grade. Based on a series of growth mixture models, one developmental trajectory best described the data. Multigroup latent growth curve models showed that girls and boys developed similarly in their arithmetic fluency over time. Symbolic magnitude processing and number sequence skills predicted both initial level and growth in arithmetic fluency, and working memory predicted only initial level, similarly for boys and girls. Mother's education level predicted the initial level of arithmetic fluency for boys, and rapid naming predicted growth for girls. Our findings highlight the role of domain-specific skills in the development of arithmetic fluency.