Clip 25/43: Standard 6: Attend to Precision Using Algebraic Equations Part 1A
Overview
Mathematically proficient students try to communicate precisely to others. They try to use clear definitions in discussion with others and in their own reasoning.
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?" The companion commentary by math coach Linda Fisher notes that “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.” Disston’s subsequent work in the lesson asks students to develop their thinking about the differences between symbol strings.