# Lesson 14

Which Equation Matches?

### Lesson Purpose

The purpose of this lesson is for students to analyze story problems and match addition and subtraction equations to them.

### Lesson Narrative

In previous lessons, students solved Take From, Start Unknown, Compare, Bigger Unknown, and Compare, Smaller Unknown problems. They showed their thinking using drawings, numbers, or words. Throughout the year, students solved all types of story problems with unknowns in all positions.

In this lesson, students learn that they can use equations to make sense of story problems in different ways. In the first activity, students sort story problems based on whether they think they best fit addition or subtraction. In the second activity, students match the same story problems to equations. In both activities, students notice that the equation that matches the actions in the story and the equation they may use to solve the problem may use the opposite operation. This discussion helps deepen students understanding of the way equations can be used to make sense of and solve problems (MP2) and their understanding of the relationship between addition and subtraction (MP7).

• Engagement
• MLR8

Activity 1: Sort Story Problems

### Learning Goals

Teacher Facing

• Analyze story problems with unknowns in all positions.
• Match addition and subtraction equations to story problems.

### Student Facing

• Let’s think about story problems and equations.

### Required Materials

Materials to Gather

Materials to Copy

• Story Problem Cards, Unknowns in All Positions

### Required Preparation

Activity 1:

• Create a set of cards from the blackline master for each group of 2.

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

What opportunities are you giving students to reflect on their understanding of the mathematical content?