The Common Core State Standards for Mathematics (CCSSM) (CCSSI 2010) define what children should understand and be able to do in K-grade 12. This document also includes a description of key mathematical processes and proficiencies, the Standards for Mathematical Practice (SMPs), which provide an important overview for the kind of robust thinking and reasoning that children should engage in. Although listed in a linear way, these standards are more effectively implemented by teachers and understood by students when they are meaningfully integrated into a rich mathematical task. In this article, the authors describe an exploration of square numbers for fourth graders that integrates five of these eight standards: (1) Make sense of problems and persevere in solving them (SMP 1); (2) Reason abstractly and quantitatively. (SMP 2); (3) Construct viable arguments and critique the reasoning of others (SMP 3); (4) Use appropriate tools strategically (SMP 5); and (5) Look for and make sense of structure (SMP 7). In planning and implementing the task the authors asked themselves, What opportunities for the standards are inherent in the task? What teacher moves might facilitate students' engagement with these standards?