Attend to precision is the sixth Mathematical Practice identified in the Common Core State Standards. Attention to precision is an overarching way of thinking mathematically, and along with the other seven mathematical practices, it is essential to the teaching and learning of all areas of mathematical content across the grades. As defined by the CCSS, the following actions are key components of what it means for students to attend to precision: communicate precisely; use clear definitions; state the meaning of symbols, including using the equal sign appropriately; specify units of measure and label axes clearly; calculate accurately and efficiently, and express answers with a degree of precision appropriate to the context of the problem.
The non-profit Education Development Center (EDC) discusses ways that the practice is applied to elementary school students. The EDC’s “Think Math” page notes the following:
“[Mathematical Practice #6’s] primary focus is precision of communication, in speech, in written symbols, and in specifying the nature and units of quantities in numerical answers and in graphs and diagrams… With experience, the concepts will become more precise, and the vocabulary with which we name the concepts will, accordingly, carry more precise meanings.”
The EDC goes on to state the following:
Curriculum and teaching must be meticulous in the use of mathematical vocabulary and symbols. For example, when students first see the = sign, it may be used in equations like 5 = 3 + 2, or in contexts like 9 + ____ = 8 + 2, in each case making clear that it signals the equality of expressions, and is not merely heralding the arrival of an answer. Teacher Guide information about vocabulary must be clear and correct, and must help teachers understand the role of vocabulary in clear communication: sometimes fancy words distinguish meanings that common vocabulary does not, and in those cases, they aid precision; but there are also times when fancy words camouflage the meaning. Therefore, while teachers and curriculum should never be sloppy in communication, we should choose our level of precision strategically. The goal of precision in communication is clarity of communication.
Communication is hard; precise and clear communication takes years to develop and often eludes even highly educated adults. With elementary school children, it is generally less reasonable to expect them to “state the meaning of the symbols they choose” in any formal way than to expect them to demonstrate their understanding of appropriate terms through unambiguous and correct use.
[Source: CCS Mathematical Practises
As students progress into the higher grades, their ability to attend to precision will increasingly expand to be more explicit and complex.