Fifty-eight children of varying math abilities, ranging in age from 7 to 8 years, were tested to investigate the influence of certain low-level cognitive abilities on their use of spatial representations of number magnitude (i.e., the so-called mental number line). A number-line estimation task and a number comparison task were administered to measure their use of the mental number line. A combined spatial-cueing and flanker task was used to assess three attention networks: executive functioning, alerting, and visual attention orienting. Visuospatial working memory was assessed with a mental rotation task, and intelligence was measured with a short-form IQ test. Regression results showed that visuospatial working memory ability was related to performance on the mental number line tasks. Hence, children with stronger visuospatial working memory ability are able to more efficiently manipulate the mental number line, and thus perform better on tasks involving understanding of number magnitude. / October 2015