Overview

This part continues work on measuring the length of the room. After measuring with a “personal ruler”, there will be an opportunity to compare and discuss results. The purpose of this discussion is to surface some of the larger issues related to measurement, including possible reasons for different measurements of the same object and questions about what differences are and are not acceptable. After this discussion, there will be an opportunity to reflect on the implications of this activity for classroom teaching, especially for how measurement might serve as a context for engagement in the mathematical practices.

Key Points

Mathematical practices (e.g., attending to precision, look for and make use of structure, use appropriate tools strategically) are a central part of the work of measuring. In elementary classrooms, measurement tasks can serve as excellent opportunities to develop skill with mathematical practices.