The purpose of this study was to determine if the achievement on correlational thinking tasks could be enhanced by a set of structured training exercises. The exercises were based on Piaget's analysis of the development of correlative thinking in adolescents. The achievement of the ninth grade students was greater than the achievement of the fifth and seventh grade students. However, some of the ninth grade students exhibited difficulty with the equivalence and reciprocal exclusion operations that were necessary for the solution of the correlation tasks. The results of the study suggest that the ninth grade students may be in the transition zone for this particular operation.