# Clip 11/13: Standard 2: Reason Abstractly & Quantitatively Using Rate of Change Part 2C

## Overview

*Mathematically proficient students make sense of quantities and their relationships in problem situations. They bring …the ability to decontextualize—to abstract a given situation and represent it symbolically and manipulate the representing symbols as if they have a life of their own…Antoinette Villarin transitions her students to a matching activity, having her students use a recording sheet to make sense of different quantities and representations, find models, match graphs, and explain their justifications for the match.*

She distributes a stack of twelve graphs that represent the flow of liquid between containers, and challenges students to match the two graphs that show movement for a given pair of containers. She notes that for some cards, information has intentionally been left out, and recommends that students begin with the cards that have complete information.

She reminds her students that they are trying to build a mathematical argument, so they must explain to their partner why a given pair of cards is a match, and the partner in turn needs to agree or disagree with each explanation. Antoinette explains how to use the cards, reminding students to refer back to the sentence frames for conversation if they don’t know what to say. This clip also relates to standard 5 (use appropriate tools strategically).