# Lesson 19

Story Problems and Equations

## Warm-up: Choral Count: 0-100 and Back Again (10 minutes)

### Narrative

The purpose of this Choral Count is to invite students to practice counting by 10 and notice patterns in the count. These understandings help students develop fluency with the count sequence and will be helpful as students begin working with numbers beyond 10.

### Launch

• "Count by 10, starting at 0."
• Record as students count.
• Stop counting and recording at 100.
• "Count backward by 10, starting at 100."
• Record as students count.
• Stop counting and recording at 0.

### Activity

• "What patterns do you see?"
• 1–2 minutes: quiet think time
• Record responses.

### Student Response

For access, consult one of our IM Certified Partners.

### Activity Synthesis

• "How did you know what number would come next as you counted backward?"

## Activity 1: Lotería (20 minutes)

### Narrative

The purpose of this activity is for students to write two equations to match each story problem. Students solve the problems in any way that makes sense to them. They may write an equation in which the total is before the equal sign, or that uses the add in any order property. Students may write equations with a box around the answer, an empty box for the unknown, or a combination of both.

The story problems in this activity are about the Mexican game, Lotería. During the launch, students learn how the game is played and some similarities between Lotería and Bingo. Before sharing information about the game, ask students if anyone has heard of this game, and what they know about how it is played. Consider showing students pictures of Lotería boards and cards.

MLR6 Three Reads. Keep books or devices closed. To launch this activity, display only the problem stem, without revealing the question. “We are going to read this story problem three times.” After the 1st Read: “Tell your partner what happened in the story.” After the 2nd Read: “What are all the things we can count in this story?” Reveal the question. After the 3rd Read: “What are different ways we can solve this problem?”
Engagement: Internalize Self-Regulation. Synthesis: Provide students an opportunity to self-assess and reflect on their own progress. For example, ask students to check over their work to make sure they used drawings, numbers, or words to solve the story problem, and also included an equation with a symbol for the unknown.
Supports accessibility for: Organization, Attention

### Launch

• Groups of 2
• “We have been solving problems about different games people play. Today we will solve problems about a game called Lotería. Has anyone played Lotería?"
• Share responses.
• If needed, "Lotería is a very popular game played in Mexico. It is similar to the game bingo. Instead of numbers, the caller picks a card with a picture on it. If the picture is on your board, you cover it. Many people use beans or small rocks to cover the pictures. When you have four pictures covered in a row you call out, ‘Lotería!’”
• Consider displaying images of the game boards and picture cards used in the game.

### Activity

• “Let’s solve some problems about students playing Lotería.”
• 6 minutes: independent work time
• “Share your equations with your partner. Explain how they match the stories.”
• 3 minutes: partner discussion

### Student Facing

1. 10 picture cards have been called.
7 of the pictures are on Mai’s board.
How many of the pictures are not on Mai’s board?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

2. Lin has 10 beans to play with.
3 of her beans fall on the floor.
How many beans does Lin have to play with now?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

3. 10 students are playing Lotería.
Some students are using beans on their boards.
Some students are using small rocks.
What are some ways to show how many students are using beans and how many are using small rocks?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

4. Noah has 3 pictures covered on his board.
His brother has 10 pictures covered.
How many fewer pictures does Noah have covered than his brother?
Show your thinking using drawings, numbers, or words.

Equation: ________________________________

Equation: ________________________________

### Student Response

For access, consult one of our IM Certified Partners.

### Activity Synthesis

• Invite students to share the equations they wrote for each story problem and explain how they match the story.

## Activity 2: What's Your Question? (15 minutes)

### Narrative

The purpose of this activity is for students to make sense of story problems that do not include a question. In some story types, like Add To, Change Unknown, students can infer what the question in the story is without it being asked. In problem types like Compare, there are multiple questions that can be answered, all of which have different equations, solutions, and methods of solving. In presenting students with problems without questions, they strengthen their understanding of connections between story problems and the equations that match. When students formulate their own questions they need to make sense of the given information in order to understand what is given and what is unknown (MP1).

• Groups of 2

### Activity

• "Now you will read story problems that don't have a question. Your job is to write a question for each problem. Then solve the problem."
• 5 minutes: independent work time
• 3 minutes: partner discussion
• Monitor for students who wrote different questions for the problem with Diego and Noah.

### Student Facing

1. Clare has 3 pictures covered on her board.
She covers some more.
Now she has 9 pictures covered.

Show your thinking using drawings, numbers, or words.

Which equation matches how you solved the story problem?

$$3 + \boxed{\phantom{6}} = 9$$

$$9 - 3 = \boxed{\phantom{6}}$$

2. Diego has 2 beans on his board.
Noah has 9 beans on his board.

Show your thinking using drawings, numbers, or words.

Which equation matches how you solved the story problem?

$$2 + \boxed{\phantom{7}} = 9$$

$$9 - 2 = \boxed{\phantom{7}}$$

### Student Response

For access, consult one of our IM Certified Partners.

### Activity Synthesis

• Invite previously identified students to share.
• Display the equations:
• $$2 + 9 = \boxed{\phantom{11}}$$
• $$9 - 2 = \boxed{\phantom{7}}$$
• $$2 + \boxed{\phantom{7}} = 9$$
• “Which question does each of these equations represent? How do you know?”

## Lesson Synthesis

### Lesson Synthesis

Write  $$3 + \boxed{\phantom{7}}= 10$$

"Today we wrote equations to match story problems. Some of the equations had an unknown value. How could you find the unknown value in this equation?"(I could count on from 3 until I got to 10. I could subtract $$10-3$$.)

## Cool-down: Beans and Rocks (5 minutes)

### Cool-Down

For access, consult one of our IM Certified Partners.