On the relation between skilled performance of simple division and multiplication.

Are corresponding multiplication and division facts (e.g., 7 x 8, 56 divided by 7) based on common or on independent memory processes? University students received division problems alternated with multiplication problems under instructions for speeded responses. Response times were highly correlated for corresponding division and multiplication problems, and error characteristics indicated parallel retrieval structures. Specifically, division errors were constrained by the distance between the dividend and the product implied by the error, rather than by distance from the correct quotient. This suggests that division memory is organized in terms of multiplicative relationships. Multiplication errors (e.g., 7 x 9 = 56) were primed by previous division trials (56 divided by 7 = 8), but division errors were not primed by previous multiplications. The error priming results suggest that multiplication is often used at least to check division.