The aims of this study were to investigate whether the executive functions, inhibition, shifting, and updating, are distinguishable as latent variables (common factors) in children aged 9 to 12, and to examine the relations between these executive functions and reading, arithmetic, and (non)verbal reasoning. Confirmatory factor analysis was used to decompose variance due to the executive and the non-executive processing demands of the executive tasks. A Shifting factor and an Updating factor, but not an Inhibition factor, were distinguishable after controlling for non-executive variance. Updating was related to reading, arithmetic, and (non)verbal reasoning. Shifting was mainly related to non-verbal reasoning and reading. However, in terms of variance explained, arithmetic and reading were primarily related to the non-executive processing demands of the executive measures. The results are discussed in light of the "task impurity problem".