# Lesson 4

## Warm-up: Verdadero o falso: Ecuaciones con 10 (10 minutes)

### Narrative

The purpose of this True or False is to give students an opportunity to deepen their understanding of the equal sign. This is the first time that students will do this instructional routine. Because equations are new to students, the teacher should read aloud each equation. When students are more familiar with equations, they will read the equations themselves when they do this routine. In the activity synthesis, students are asked to reword another student's thinking and justify the answer in a different way (MP3).

### Launch

• Display one statement.
• “Hagan una señal cuando sepan si la afirmación es verdadera o no, y puedan explicar cómo lo saben” // “Give me a signal when you know whether the statement is true and can explain how you know.”
• 1 minute: quiet think time

### Activity

• Share and record answers and strategy.
• Repeat with each equation.

### Student Facing

Prepárate para explicar tu razonamiento.

• $$10 = 10$$
• $$4 + 6 = 10$$
• $$2 + 7 = 10$$

### Activity Synthesis

• “¿Alguien puede expresar el razonamiento de _____ de otra forma?” // “Who can restate _____'s reasoning in a different way?”
• “¿Alguien quiere agregar algo al razonamiento de _____?” // “Does anyone want to add on to _____’s reasoning?”

## Activity 1: Comparemos los problemas (15 minutes)

### Narrative

The purpose of this activity is for students to represent and solve an Add To, Result Unknown or Change Unknown story problem. Students then compare each problem, including how the problem is written and how the problem is solved. Each group creates a representation and writes an equation to match one of the problems. Groups then pair up to share their work. Students attend to precision and use clear and precise language to explain how they solved and represented the problem (MP6). The activity synthesis draws out differences in the story problems as well as differences in how they are solved.

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• Give students tools for creating a visual display and access to 10-frames and connecting cubes or two-color counters.
• “Hoy vamos a resolver más problemas-historia. Los problemas de hoy son acerca de distintos tipos de libros. ¿Qué tipos de libros les gusta leer?” // "Today we are going to solve more story problems. The problems today are about different kinds of books. What kinds of books do you like to read?"
•  30 seconds: quiet think time
• 2 minutes: partner discussion
•  Share responses.
•  “Veamos qué tipos de libros les gusta leer a las personas de nuestras historias” // "Let's see what kinds of books the people in our stories like to read."

### Activity

• Assign each group one of the problems.
• “Hagan un póster que muestre su respuesta al problema. El póster debe tener un dibujo y una ecuación. Prepárense para explicar cómo lo resolvieron y cómo supieron qué ecuación escribir” // “Make a poster that shows your answer to the problem. It must have a drawing and an equation. Be ready to explain how you solved it and how you knew what equation to write.”
• 5 minutes: partner work time
• “Ahora busquen otra pareja que haya resuelto el otro problema y trabajen con ellos. Cada pareja comparte su póster y también cuenta cómo resolvieron el problema y cómo saben que la ecuación que escribieron corresponde al problema-historia” // "Now find another group to work with that solved the other problem. Each group of 2 shares their poster, including how they solved the problem and how they know the equation they wrote matches the story problem.”
• 4 minute: small group discussion

### Student Facing

1. Mai tiene 5 novelas gráficas.
¿Cuántas novelas gráficas tiene ahora?
Muestra cómo pensaste. Usa dibujos, números o palabras.

Ecuación: ________________________________

2. Mai tiene 5 novelas gráficas.
Ahora tiene 9 novelas gráficas.
Muestra cómo pensaste. Usa dibujos, números o palabras.

Ecuación: ________________________________

### Activity Synthesis

• Display both problems and student posters of how each problem was solved.
• “¿Qué diferencias ven entre los dos problemas-historia?” // “What differences do you see between the two story problems?” (In problem 1, we know how many books Mai checked out, but in problem 2 we don’t. In problem 1 we don’t know how many books she has total, but in problem 2 we do.)
• “¿Cómo influyen estas diferencias en la forma como resuelven el problema?” // “How do these differences affect how you solve the problem?” (In problem 1, we just drew 5 books and 4 more books. Then we had to count how many there were altogether. In problem 2, we had to start with 5 books, and draw more until we had 9. Then count how many more we drew.)

## Activity 2: Problemas-historia sobre libros (20 minutes)

### Narrative

The purpose of this activity is for students to solve a variety of Add to and Take from Result or Change Unknown story problems. Students solve the story problems any way they choose and write an equation that matches the story and has a box around the answer to the question. During the activity synthesis, students consider the different ways to write equations for a story problem.

MLR8 Discussion Supports. Synthesis: For each method that is shared, invite students to turn to a partner and restate what they heard using precise mathematical language.
Engagement: Develop Effort and Persistence. Chunk this task into more manageable parts. Check in with students to provide feedback and encouragement after each chunk.
Supports accessibility for: Social-Emotional Functioning, Attention

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• Give students access to 10-frames and connecting cubes or two-color counters.
• “Vamos a resolver más problemas-historia sobre libros que les gusta leer a otros niños” // "We are going to solve some more story problems about books other kids like to read."

### Activity

• 5 minutes: independent work time
• 5 minutes: partner discussion

### Student Facing

1. Mai ha leído 3 libros sobre perros.
Diego le da 4 libros más para leer.
¿Cuántos libros sobre perros leerá Mai en total?
Muestra cómo pensaste. Usa dibujos, números o palabras.

Ecuación: ________________________________

2. Noah tiene 4 libros de poesía.
Su hermana le da más libros.
Ahora él tiene 10 libros de poesía.
¿Cuántos libros le dio su hermana?
Muestra cómo pensaste. Usa dibujos, números o palabras.

Ecuación: ________________________________

3. Tyler tiene 7 libros sobre arañas.
Él le da 3 de sus libros a Kiran.
¿Cuántos libros le quedan a Tyler?
Muestra cómo pensaste. Usa dibujos, números o palabras.

Ecuación: ________________________________

4. Lin tiene 5 libros sobre el espacio exterior.
El profesor le da más libros a Lin.
Ahora Lin tiene 10 libros sobre el espacio exterior.
¿Cuántos libros le dio el profesor a Lin?
Muestra cómo pensaste. Usa dibujos, números o palabras.

Ecuación: ________________________________

### Activity Synthesis

• Invite students to share the equation for each problem.
• “¿Por qué la respuesta está en lugares diferentes de nuestras ecuaciones?” // "Why is the answer in different places in our equations?" (Because in some stories we know the two numbers to add together and then the answer is the total. In other problems we know the starting number and the total and the answer is the other number we added.)

## Lesson Synthesis

### Lesson Synthesis

Display the problem about Lin's books and $$5 + \boxed{\phantom{5}} = 10$$.

“Hoy escribimos ecuaciones que correspondían a problemas-historia y discutimos diferencias entre las ecuaciones. Vean el problema y la ecuación. ¿Qué observan? ¿Qué se preguntan?” // “Today we wrote equations to match story problems and discussed differences in the equations. Look at the problem and the equation. What do you notice? What do you wonder?” (I see a blank box. I notice the equation matches the story problem. It starts with 5, then some more are added, and that is the same amount as 10. I wonder if 5 goes in the blank box.)

If needed, ask “¿Cómo se relaciona este problema-historia con la ecuación $$5 + \boxed{\phantom{5}} = 10$$?” // “How does this story problem connect to the equation $$5 + \boxed{\phantom{5}} = 10$$ ?” ($$5 + \boxed{\phantom{5}}$$ represents Lin’s 5 books and the number of books her teacher gives her. The 10 represents how many books she has about outer space now. The blank box is where the 5 goes since that is the answer to the question.)

## Student Section Summary

### Student Facing

Resolvimos problemas-historia y los representamos con objetos, dibujos, palabras y ecuaciones.

• Resolvimos problemas-historia usando una suma.

Mai ha leído 3 libros sobre perros.
Diego le da 4 libros más para leer.
¿Cuántos libros sobre perros leerá Mai en total?

• Resolvimos problemas-historia usando una resta.

Tyler tiene 7 libros sobre arañas.
Él le da 3 a Kiran para que los lea.
¿Cuántos libros le quedan a Tyler?

• Resolvimos problemas-historia en los que el cambio era desconocido.

Lin tiene 5 libros.
Su profesor le da más libros.
Ahora ella tiene 10 libros para leer.
¿Cuántos libros le dio su profesor?

• Aprendimos que el signo igual significa “la misma cantidad que” y “es igual a”.