# Clip 8/20: Problem 1 - Part D

## Overview

Jacob Disston asks his students to focus on a category of symbol strings (expression, equation, inequality), separate them, and discuss how they know how to categorize them. Students are asked to make statements like "I know this is an equation because..." or "I think ... what do you think?"

## Teacher Commentary

COMMENTARY BY COACH LINDA FISHER: These clips bring up the importance of creating opportunities for students to use mathematical vocabulary for a purpose. While everyone is using the same language of equations, students seem to have a variety of definitions for what that means. Some students name it an equation because there’s multiplication. For others the variable signifies equations. Students seem to puzzle over words for describing signs: there’s addition, subtraction, and other signs like equal. They understand that the difference is significant, but don’t know how to classify it. How do you think about things you can’t name? As adults, we sometimes take meanings for granted. Equation seems like an obvious or given definition, but as I listen to students in the clips I hear many meanings or unintentional learning that they have attached to the word. Notice that even the writing promotes further discussion and negotiation of the definitions.