The aim of the present study was to investigate the contribution of working memory and verbal ability (measured by vocabulary) to mathematical skills in children. A sample of 206 seven- and eight-year-olds was administered tests of these cognitive skills. A different pattern emerged that was dependent on both the memory task and the math skill. In the seven-year olds, visuo-spatial and verbal memory uniquely predicted performance on the math tests; however, in the eight-year olds, only visuo-spatial short-term memory predicted math scores. Even when differences in vocabulary were statistically accounted, memory skills uniquely predicted mathematical skills and arithmetical abilities. This pattern of findings provides a useful starting point that can add to existing research on the contributions of working memory and vocabulary to different mathematical skills.