By following learned rules rather than reasoning, students often fall into common error patterns, something every experienced teacher has observed in the classroom. In their effort to circumvent the developing common error patterns of their students, the authors decided to supplement their math text with two weeklong investigations. The first was an adaptation of a section from "Developing Place Value Number Concepts" (Richardson 1998). The second unit was part of an investigation titled "The T-Shirt Factory: Place Value, Addition, and Subtraction" (Fosnot 2008b). These investigations challenged their students' intellects as they explored, reasoned, and justified their solutions--engaging them in higher-level thinking. By sharing their experiences, the authors hope that other teachers will feel empowered to supplement their curriculum with place-value activities to support and create meaning of the base-ten place-value system. (Contains 3 figures.)