Unpacking Referent Units in Fraction Operations

  • Unpacking Referent Units in Fraction Operations

    Randolph A. Philipp and Casey Hawthorne
    Using cups of sugar, this sequence of division tasks for K–grade 12 and adult learners highlights how seeing “wholes” results in fewer “holes” in reasoning.
    Although fraction operations are procedurally straightforward, they are complex, because they require learners to conceptualize different units and view quantities in multiple ways. Why, when dividing fractions, do we invert and multiply? Prospective secondary school teachers sometimes provide an algebraic explanation. This proof may leverage the elegance of algebraic symbolic manipulation (see fig. 1), but it does not address the underlying relationships that are so important for learners striving to understand fractions. Furthermore, we know that secondary and elementary school preservice teachers have difficulty providing a conceptual explanation for fraction division (Ball 1990; Borko et al. 1992), and we have found that most experienced teachers have not had opportunities to work through, in a meaning-making way, the principles associated with making sense of fraction division.