# Lesson 15

Different Types of Story Problems

## Warm-up: Which One Doesn’t Belong: Equations (10 minutes)

### Narrative

This warm-up prompts students to compare four equations. It gives students a reason to use language precisely (MP6). It gives the teacher an opportunity to hear how students use terminology and talk about characteristics of the items in comparison to one another. During the synthesis, ask students to explain the meaning of the equal sign in their reasoning.

### Launch

• Groups of 2
• Display the image.
• “Pick one that doesn’t belong. Be ready to share why it doesn’t belong.”
• 1 minute: quiet think time

### Activity

• 2–3 minutes: partner discussion
• Record responses.

### Student Facing

Which one doesn’t belong?

1. $$7 = \boxed7$$

2. $$\boxed7 = 3 + 4$$

3. $$4 + 3 = \boxed8$$

4. $$7 - 3 = \boxed4$$

### Activity Synthesis

• “What does each equation help us know about the equal sign?” (It shows us that the equal sign means the amount on either side is the same.)

## Activity 1: What Questions Can We Ask? (10 minutes)

### Narrative

The purpose of this activity is for students to make sense of a problem before solving it by familiarizing themselves with a context and the mathematics that might be involved (MP1). Students are asked to tell a story about an image in order to generate observations that lead them to ask mathematical questions about the context. This sets them up for Activity 2 in which students will be solving story problems in the given context.

MLR8 Discussion Supports. Display sentence frames to support partner discussion: "The picture shows. . . ." and “I can count. . . .”

### Launch

• Groups of 2
• “Use numbers to describe the image.”
• 1 minute: quiet think time
• 2 minutes: partner discussion
• Share responses.

### Activity

• 3 minutes: independent work time
• 2 minutes: partner discussion
• Monitor for students who are asking questions about how many altogether or how many more or fewer.

### Activity Synthesis

• Invite several students to share one question with the class.
• Record responses.
• If needed, ask, “Can this question be answered by the image? How do you know?”
• “What do these questions have in common? How are they different?” (Some of them use the same numbers. Some ask to find the total and others ask to find the difference.)

## Activity 2: Different Types of Problems (15 minutes)

### Narrative

The purpose of this activity is for students to solve a variety of story problems and write addition and subtraction equations that match those problems. Students solve Put Together/Take Apart, Total or Addend Unknown problems and Compare, Difference Unknown problems. Students may solve in any way they want and write equations to match the story problem, putting a box around the number that represents the answer (MP2).

Action and Expression: Internalize Executive Functions. Invite students to plan a method, including the tools they will use, for representing and solving the story problems. If time allows, invite students to share their plan with a partner before they begin.
Supports accessibility for: Organization, Conceptual Processing

• Groups of 2

### Activity

• “You will solve problems about the picture from the warm up. The questions may include some of the questions you asked. Show your thinking using drawings, numbers, or words. Write an equation to match the story problem. If you can, write two different equations that match the problem.”
• 6 minutes: independent work time
• 4 minutes: partner discussion
• Monitor for students who solved using drawings, can clearly explain how they solved, and wrote an equation.

### Student Facing

1. There are 8 people at the table.
6 of the people are students.
How many are teachers?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

2. Elena has 4 pattern blocks.
Tyler has 6 pattern blocks.
How many fewer pattern blocks does Elena have than Tyler?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

3. Tyler has 6 pattern blocks.
Elena has 4 patterns blocks.
How many pattern blocks do they have altogether?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

4. Priya has 7 triangles and 3 squares.
How many more triangles than squares does Priya have?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

### Activity Synthesis

• Display: Elena has 4 pattern blocks. Tyler has 6 pattern blocks. How many fewer patterns blocks does Elena have than Tyler?
• “How did you solve this problem? What equation did you write?”
• Record student methods and equations.
• Repeat for the other problems with the same numbers.
• “How are these problems the same? How are they different?” (They both have Elena and Tyler. They both have 4 and 6. In one we find the difference and in the other one we find the total. The answers are different.)
• If needed, ask, “Is the total important to solving the first problem? Why or why not?” (No, because we are comparing the students.)

## Activity 3: Centers: Choice Time (15 minutes)

### Narrative

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 10. Students choose from any stage of previously introduced centers.

• Capture Squares
• Shake and Spill
• What’s Behind My Back

### Required Materials

Materials to Gather

### Required Preparation

• Gather materials from previous centers:
• Capture Squares, Stage 1
• Shake and Spill, Stages 3 and 4
• What's Behind My Back, Stage 2

### Launch

• Groups of 2
• “Now you are going to choose from centers we have already learned.”
• Display the center choices in the student book.
• “Think about what you would like to do.”
• 30 seconds: quiet think time

### Activity

• Invite students to work at the center of their choice.
• 10 minutes: center work time

### Student Facing

Choose a center.

Capture Squares

Shake and Spill

What's Behind My Back

### Activity Synthesis

• Using a tower of 8 cubes, break the tower and hide one part behind your back.
• “What’s behind my back? How do you know?”
• Write equations to match student methods.

## Lesson Synthesis

### Lesson Synthesis

Display $$7 - 2 = \boxed{5}$$ and $$2 + \boxed{5} = 7$$.

“Today we wrote different equations to match the same story. Tell a story that could match both of these equations.” (I have 7 balloons. My friend has 2 balloons. How many more balloons do I have than my friend?)

## Student Section Summary

### Student Facing

• We made cube towers that have the same number of cubes.

We can add 7 more blue cubes.
We can take off 7 red cubes.

• We solved story problems about “how many more” and “how many fewer.”

Elena has 4 pattern blocks.
Tyler has 6 pattern blocks.
How many fewer pattern blocks does Elena have than Tyler?

$$4 + \boxed{2} = 6$$

or

$$6 - 4 = \boxed{2}$$

• We learned that these problems can be solved with addition or subtraction.