This paper describes a computer model that simulates the way children develop the reasoning skills of transitive inference and the construction of ordered sets. The computer model begins from general operations, such as setting and removing goals, storing and retrieving information, comparing elements to find matches, reading premises, and giving feedback. The program sometimes produces errors due to processing and memory storage difficulties. The model implies that the development of reasoning involves the development of strategies, and that strategies are built on general and specific knowledge acquired through everyday experience. A list of 14 references is included. (BC)