Key elements in the construction of an operation were an integral part of an empirical study designed to test practical, pedagogical implications of the Piagetian model of cognitive growth. A total of 49 kindergarten children were pretested to determine their levels of seriation and classification operations. Pretests were conducted with a battery of Piagetian tasks that had been refined in a pilot study involving 50 additional children. Subjects were observed in a classroom where a learning center was equipped with a manipulative number board designed to foster seriation and classification skills. The number board was available in a free-choice format during a "free-play" activity hour, 4 days a week for a total of 15 days. Children were then posttested. It was predicted that children in transitional phases of constructing logical operations would freely choose to use the board more than children would who had already constructed these operations or were not close to constructing them. Decalage, which was based on how much variability existed among test sores measuring the same operation, was used as an index to determine which children were experiencing internal cognitive conflict. As predicted, children with the highest decalage scores used the manipulative number board significantly more often and with greater variety than did their low decalage counterparts. Board use was found to be significantly associated with gain in seriation scores. (RH)