Despite the fact that developing critical thinking represents an important task of mathematics education, there are numerous open questions when it comes to its realization. One part of these problems stems from its generalization and indeterminancy, another from the lack of a clear strategy for its development. In this paper, we attempted to operationalize the concept of critical thinking in the context of elementary mathematics education, through specific skills that are emphasized during work with mathematical content and to examine if a more purposeful selection of content can influence the development of critical thinking.