The path towards mathematics success starts early, as initial numerical knowledge sets the foundation for children’s later mathematics learning. In particular, young children’s knowledge of numerical magnitudes, like knowing that seven is more than three, is theorized to play an important role in their mathematical development. In support of this perspective, there is consistent evidence that symbolic magnitude skills, or knowledge of how written numerals and number words can be ordered and compared, predict mathematical achievement in childhood and adulthood. Yet less is known about the antecedents and consequents of symbolic magnitude understanding in preschool. The goal of the present study was to understand whether symbolic magnitude knowledge in early childhood relates to later math achievement and identify foundational numerical and general cognitive skills that underlie the development of symbolic magnitude knowledge.

One hundred and forty Head Start preschoolers aged 3 – 5 years old were assessed in the winter and spring of the school year to test a theory-driven conceptual model of symbolic magnitude development. Specifically, children’s knowledge of the cardinal value represented by numbers, such as knowing that the number word “four” can be represented with four objects, was hypothesized to predict their symbolic magnitude understanding, with children’s symbolic magnitude understanding in turn predicting their symbolic addition skills controlling for children’s executive functioning skills, age, and gender.

There was significant evidence in favor of the proposed conceptual model, specifically that children’s cardinality skills predicted their concurrent and later symbolic magnitude understanding; children’s symbolic magnitude understanding predicted their later addition skills; and children’s executive functioning skills predicted each of their numerical skills uniquely. Findings suggest symbolic magnitude understanding fully mediates the relation between children’s cardinality and addition skills, and both domain-general executive functioning and domain-specific cardinality and magnitude skills assessed in the winter explain a similar amount of variability in children’s spring addition skills. These findings will be used to inform the design of comprehensive early numeracy interventions to help parents, teachers, and researchers best support the mathematical development of young children.