Twenty Hong Kong Chinese undergraduate students were recruited to examine the patterns of the odd-even effect observed in Lemaire and Fayol (1995). In the present study, the odd-even effect was found only in difllcult problems for which problems and answers were presented simultaneously. Since participants in the present study were believed to possess faster retrieval speed than those in Lemaire and Fayol (1995), the results suggest that memory retrieval and parity-checking are executed in parallel, and are consistent with the multiple-strategy hypothesis which states that there is a horse race between the fact retrieval and parity-checking processes during verification. Implications about the superiority of Chinese in solving simple arithmetic are also discussed.

Key words: odd-even effect, multiple-strategy, strategy execution arrangement, product verification, arithmetic processing