# Lesson 6

Problemas-historia de comparación

## Warm-up: Cuál es diferente: Ecuaciones (10 minutes)

### Narrative

This warm-up prompts students to carefully analyze and compare equations. In addition to calculating the value of each expression, students also think about the structure of each expression, including both the operations and the numbers (MP7). In the synthesis, students compare an equation with addition and an equation with subtraction to focus student attention on comparing operations and reasoning about the relationship between addition and subtraction.

### Launch

• Groups of 2
• Display image.
• “Escojan una que sea diferente. Prepárense para compartir por qué es diferente” // “Pick one that doesn’t belong. Be ready to share why it doesn’t belong.”
• 1 minute: quiet think time

### Activity

• “Discutan con su pareja cómo pensaron” // “Discuss your thinking with your partner.”
• 2-3 minutes: partner discussion
• Share and record responses.

### Student Facing

¿Cuál es diferente?

1. $$10 = 6 + 4$$
2. $$16 - 5 = 11$$
3. $$11 = 6 + 4 + 1$$
4. $$3 + 8 = 11$$

### Activity Synthesis

• Display equations B and C.
• “¿En qué se parecen las ecuaciones? ¿En qué son diferentes?” // “How are the equations the same? How are they different?” (They both have the value 11. The first equation uses subtraction while the second one uses addition. The 11 is on the right hand side in the first equation and on the left hand side in the second equation. In the second equation 11 is written using three numbers and there are only two in the first equation.)

## Activity 1: La feria de la escuela (20 minutes)

### Narrative

The purpose of this activity is for students to practice solving Compare, Difference Unknown story problems (MP2). In the synthesis, students revisit a representation of a Compare problem that was introduced in a previous unit. This representation lays the foundation for working with tape diagrams in grade 2.

The teacher may want to incorporate movement into this activity by writing each problem on a piece of chart paper and placing each one in a different location around the classroom. Students can solve the problem at one location, discuss the problem with their partner, then move on to a new problem at a new location.

Representation: Access for Perception. Provide appropriate reading accommodations and supports to ensure student access to word problems and other text-based content.
Supports accessibility for: Language, Visual-Spatial Processing, Attention

### Launch

• Groups of 2
• Give each group access to connecting cubes in towers of 10 and singles.
• “Hoy vamos a resolver algunos problemas sobre una feria escolar. Mencionen algunas cosas que sepan sobre las ferias” // “Today we are going to solve some problems about a school carnival. What are some things you know about carnivals?” (There are rides. You can play games. There is lots of food.)

### Activity

• 8 minutes: independent work time
• 4 minutes: partner work time
• For the problem about prizes, monitor for students who:
• use cubes or draw pictures to represent both quantities.
• write equations with a symbol to represent the unknown.
• write equations to show how they used addition or subtraction to find the difference.

### Student Facing

Resuelve todos los problemas.
Muestra cómo pensaste. Usa dibujos, números o palabras.

1. Lin tiene 7 boletos para las atracciones.
Mai tiene 12 boletos.
¿Cuántos boletos más que Lin tiene Mai?

2. En el puesto de algodón de azúcar vendieron 17 bolsas de algodón de azúcar azul.
Vendieron 7 bolsas de algodón de azúcar rosado.
¿Cuántas bolsas más de algodón azul que de algodón rosado vendieron?

3. Tyler escoge un premio.
Hay 13 juguetes y 9 animales de peluche.
¿Cuántos animales de peluche menos que juguetes hay?

4. En la rueda de la fortuna caben 20 personas.
En los columpios caben 14 personas.
¿Cuántas personas menos caben en los columpios que en la rueda de la fortuna?

### Student Response

• “¿De qué se trata el problema? ¿Qué sabes? ¿Qué necesitas averiguar?” // “What is the problem about? What do you know? What do you need to figure out?”
• “¿Qué hiciste para resolver el problema?” // “What did you do to solve the problem?”
• “¿Qué significa tu respuesta en la historia? ¿Tiene sentido?” // “What does your answer mean in the story? Does it make sense?”
• “¿Cómo podrías usar los cubos encajables o un dibujo para representar el problema?” // “How could you use the connecting cubes or a drawing to represent the problem?”

### Activity Synthesis

• Invite previously identified students to share.
• “Expliquen cómo estas representaciones corresponden a la historia” // “How do these representations match the story?”
• If needed, “¿En qué parte de esta representación ven cuántos animales de peluche menos que juguetes hay?” // “Where do you see how many fewer stuffed animals there are than toys?”
• If needed, “¿Qué ecuaciones podemos escribir para representar este problema?” // “What equations can we write to represent this problem?”

## Activity 2: ¿Cuántas atracciones? (20 minutes)

### Narrative

The purpose of this activity is for students to use given information to ask and answer different questions. Students may ask Put Together or Compare problems using the given information. A representation of the information is also provided. This representation is a precursor to the tape diagrams students will use to represent and solve Compare problems in grade 2.

When students recognize the mathematical features of things in the real world and ask questions that arise from a presented situation, they model with mathematics (MP4).

MLR2 Collect and Display. Circulate, listen for and collect the language students use as they create questions to match each task statement. On a visible display, record comparison words and phrases such as: more than, less than, how many fewer, and how many more. Invite students to borrow language from the display as needed, and update it throughout the lesson.

### Launch

• Groups of 2
• Give each group access to connecting cubes in towers or 10 and singles.

### Activity

• 15 minutes: partner work time
• Monitor for students who can explain how the representation helps them answer the question they asked.

### Student Facing

Usa la información para escribir y responder 2 preguntas.
Si te ayuda, usa el dibujo para la primera situación.

1. Diego montó en 17 atracciones.
Priya montó en 11 atracciones.

2. Jada montó en 3 atracciones.
Kiran montó en 6 atracciones.
Noah montó en 9 atracciones.

### Activity Synthesis

• Display the representation in the student book.
• Invite previously identified students to share their question and how the representation helps them find the answer to the question.

## Lesson Synthesis

### Lesson Synthesis

Display:

Mai went on 6 rides.

“Hoy hicimos y respondimos preguntas tipo ‘cuántos más’ y ‘cuántos menos’. ¿Qué preguntas podemos hacer sobre esta información?” // “Today we asked and answered ‘how many more’ and ‘how many fewer’ questions. What questions can we ask about this information?” (How many more rides did Jada go on than Mai? How many fewer rides did Mai go on than Jada?)

Display equation:

6 + 3 = 9

“¿Cómo se ve en la ecuación la relación entre las atracciones en las que Jada y Mai montaron?” // “How does the equation show the relationship between the rides Jada and Mai went on?” (It shows that you have to add three more rides to Mai’s rides in order to get to the number of rides Jada went on.)