In the buzzing activity of the mathematics classroom, teaching in a way that effectively responds to and furthers students' thinking can be quite challenging. Given that teachers' instructional decisions will directly influence students' learning, it is extremely important to develop the sorts of practices that lead to productive in-the-moment teaching choices. Teachers have the opportunity to engage in professional noticing in every instructional situation; however, this practice is more complex than merely observing students and their work. Jacobs, Lamb, and Philipp (2010) defined professional noticing as "a set of three interrelated skills: attending to children's strategies, interpreting children's understandings, and deciding how to respond on the basis of children's understandings" (p. 172). To emphasize each of the three interrelated skills, it is useful to slow down one's instructional thought process and consider them separately yet progressively.