The present study tests two predictions stemming from the hypothesis that a source of difficulty with rational numbers is interference from whole number magnitude knowledge. First, inhibitory control should be an independent predictor of fraction understanding, even after controlling for working memory. Second, if the source of interference is…

This study explored whether kindergarteners who had yet to learn about multi-digit numbers at school could automatically process the underlying magnitudes, i.e., place-values, represented by the digits in a multi-digit number. A place-value Stroop task showed a pair of price tags in each trial. Each price tag contained a three-digit number, of…