General and math-specific predictors of sixth-graders’ knowledge of fractions

•Examined fifth grade predictors of sixth grade fraction concepts and procedures.•Number line estimation uniquely predicted fraction concepts and procedures.•Proportional reasoning predicted conceptual understanding of fractions.•Division, working memory, attention, and multiplication fluency predicted outcomes.

The present study examined predictors of student's knowledge of fraction concepts and procedures in sixth grade (N = 334). Predictors included both math-specific and more general competencies, which were assessed in fifth grade. Multiple regression analyses showed that whole number line estimation, non-symbolic proportional reasoning, long division, working memory, and attentive behavior contributed uniquely to a general measure of students’ fraction concepts; on a measure of fraction procedures, whole number line estimation, multiplication fact fluency, division, and attention made unique contributions. The combined predictability of the measures was lower for fraction procedures than for fraction concepts. Although the unique predictors and the amount of explained variance differed according to the fraction outcome, the ability to locate whole numbers on the number line was a major contributor to prediction in each model. Non-symbolic proportional reasoning was particularly predictive of children's conceptual understanding of fractions.