## Understanding Practice Standard 6: Attend to Precision

The Common Core’s Mathematical Practice 6, Attend to Precision, calls for students to be careful in their reasoning, calculation, and communication through the precise use of words, symbols, units of measure, mathematical expressions, and processes. Students recognize various levels of precision and apply them appropriately, for example, by determining when an estimate is sufficient or more appropriate than an exact answer. When an exact answer is called for, they calculate it accurately and efficiently.

## Why is precision important?

The clarity fostered by these habits of mind is a hallmark of mathematical thinking. In addition to the obvious need to communicate clearly with others, being precise per se fosters greater conceptual development and higher order thinking. For example, the confusion many children have with regard to the equal sign has critical implications for their understanding of the larger concept of equivalence, on which much of mathematics is based. Specifying units of measure gives meaning to a calculation and helps a student judge its reasonableness. Labeling graphs helps a student analyze and interpret them. Once they understand the concepts behind computations, we want students to master procedures and algorithms that allow them to solve problems accurately and efficiently, so that more attention can be paid to problem solving and deeper thinking.

## How should we develop precision?

Like other Mathematical Practices, MP 6 is best addressed in the context of doing worthwhile mathematics. Rich problems and investigations provide authentic opportunities to apply and hone these dispositions. Students learn to be precise in their communication by hearing their teachers model correct math language and by explaining their thinking to their peers, first with math talk and then in writing, whether through pictures, diagrams, symbols, or words. Problem solving offers a meaningful context in which to develop vocabulary and address aspects of precision in a way that helps learners internalize them and appreciate their importance.

## How can these resources help?

The resources in this collection are intended to help teachers and math specialists understand the intent and scope of MP 6 and plan for successful attainment in the classroom. They include resources that help us interpret the practice and appreciate its importance and videos that illustrate teachers fostering the practice with their students. Several resources offer suggestions for vocabulary development as well as general strategies that promote precision, including explicit modeling, formats for sharing student thinking, and problem solving approaches.

A companion classroom collection, Implementing MP 6: Attend to Precision, includes resources to help teachers foster this practice with their students.

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