A "Framework for K-12 Science Education" identified eight practices as "essential elements of the K-12 science and engineering curriculum" (NRC 2012, p. 49). Most of the practices, such as Developing and Using Models, Planning and Carrying Out Investigations, and Analyzing and Interpreting Data, are well known among science educators. In contract, the practice of Using Mathematics and Computational Thinking raises questions in the minds of many educators. As mathematics has long been integral to science teaching, the questions tend to revolve around the meaning of computational thinking. The authors present a Venn diagram that shows how they see the relationship between mathematical and computational thinking. The diagram shows which capabilities can be considered part of mathematical thinking, which are part of computational thinking, and which are part of both. As the diagram illustrates, analyzing and interpreting data is common to both mathematical and computational thinking, as are problem solving, mathematical modeling, and statistics and probability. The authors give examples designed to support student learning of a number of performance expectations in the "Next Generation Science Standards." Each example is accompanied by a performance expectation from the standards and the practice that is combined with computational thinking that students are expected to demonstrate when meeting the performance expectation.