In this paper, we report on a study aimed at identifying mathematical problem solving in a preschool activity. Observations of mathematical activity with 9 preschool children have been analyzed in accordance with Variation Theory principles for how new aspects of phenomena can be discerned to identify necessary conditions for an activity to be considered problem solving. We have identified two such conditions. The first is attentiveness to different approaches in completing a task. The second is the availability of different types of activities open for children to transcend the given features of a task. The results show how the planned activity in empirical focus gives children limited opportunity to distinguish and work with problem solving. We argue that the results of this study can be used as a starting point in the planning of mathematical problem solving and to help preschool teachers in developing their work, but also to facilitate future research on the topic.