# Lesson 26

Feria del libro (optional)

## Warm-up: Observa y pregúntate: Venta de libros (10 minutes)

### Narrative

The purpose of this warm-up is to introduce the idea of a book sale, which will be useful when students work with this context in a later activity. While students may notice and wonder many things about these images, the range of and prices and types of books are the important discussion points.

### Launch

• Groups of 2
• Display the image.
• “¿Qué observan? ¿Qué se preguntan?” // “What do you notice? What do you wonder?”
• 1 minute: quiet think time

### Activity

• “Discutan con su pareja lo que pensaron” // “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Share and record responses.

### Student Facing

¿Qué observas? ¿Qué te preguntas?

### Activity Synthesis

• “¿En qué cosas debemos pensar cuando planeamos una feria del libro para nuestra escuela?” // “What are some things we have to think about if we plan a book fair for our school?” (The different types of books we sell and have to order, the cost of the books for us, the amount to charge for each book, the number of people who come to the fair, and the number of books that we sell.)

## Activity 1: Precios de libros (20 minutes)

### Narrative

In this activity students compare two book sale scenarios in which there is a different base price of a book for the fundraiser. Students notice that when you increase the price by a lot, you make more profit per book, but you may also sell fewer books. On the other hand, if you increase the price by less money, you have to sell more books to make the same profit.

MLR6 Three Reads. Keep books or devices closed. Display only the problem stem, without revealing the questions. “Vamos a leer este problema 3 veces” // “We are going to read this question 3 times.” After the 1st Read: “Díganle a su compañero de qué se trata esta situación” // “Tell your partner what this situation is about.” After the 2nd Read: “Hagan una lista de las cantidades. ¿Qué se puede contar o medir?” // “List the quantities. What can be counted or measured?” Reveal the question(s). After the 3rd Read: “¿Qué estrategias podemos usar para resolver este problema?” // “What strategies can we use to solve this problem?”

### Launch

• Groups of 2
• “Cuando en una escuela se planea vender libros para recolectar fondos, la escuela pide libros de cierto precio a la editorial o a la librería. Luego, los libros se venden a otro precio durante la feria del libro de la escuela” // “When a school plans a book sale fundraiser, the school orders books from the publisher, or bookseller, for a certain price. Then the school sells it for a different price at the book fair.”
• “Imaginemos que en la escuela compran un libro que cuesta \$10. ¿En la feria del libro deberían venderlo por más o por menos de \$10? ¿Por qué?” // “Let’s imagine the school buys a book for \$10. Should they sell the book for more or less than \$10 at the book fair? Why?” (More if they want to make money from the sale.)
• “Este se llama el precio con ganancia. Por cada libro que se venda, la librería obtendrá \$10 y en la escuela se quedarán con el dinero que se le sumó al precio inicial. El dinero que se le suma al precio inicial se llama la ganancia” // “This is called the mark-up price. For every book they sell, the bookseller will get \$10 and the school keeps the amount they added. The amount they add is called the profit.”

### Activity

• 1 minute quiet think time
• 5 minutes: group work time
• Monitor for students who consider the profit per book in their justifications.

En dos escuelas le compran libros de ciencias a una editorial, a \$8 cada uno. En la feria de la escuela A los venden a \$12, mientras que en la feria de la escuela B los venden a \$12.90. 1. ¿En cuál escuela crees que se van a vender más libros de ciencias? ¿Por qué? 2. Si en cada escuela se venden 35 libros, ¿cuántas ganancias se obtienen en cada una? 3. En la escuela B se venden 10 libros de ciencias. ¿Cuántos libros de ciencias se tienen que vender en la escuela A para recolectar la misma cantidad de dinero? ### Student Response Teachers with a valid work email address can click here to register or sign in for free access to Student Response. ### Activity Synthesis • “¿Cuál es un precio con ganancia razonable?” //“What is a reasonable mark-up price?” • “¿Qué deben considerar al decidir un precio con ganancia?” // “What do you need to consider when deciding a mark-up price?” ## Activity 2: Planeemos una feria del libro (20 minutes) ### Narrative In this activity students plan a school book fair. They choose the types of books to order and the cost for each type of book. They also estimate how many people might come to the book fair and how much money the school might raise through the book sale. Students will have to make many assumptions in this activity: how many people are coming, how many books each person will buy, and how much to add to the price of the book, to name a few. When students are explicit about assumptions, they model with mathematics (MP4). Engagement: Develop Effort and Persistence. Invite students to generate a list of shared expectations for group work. Record responses on a display and keep visible during the activity. Supports accessibility for: Language, Social-Emotional Functioning, Organization ### Launch • Groups of 2 • “En esta actividad van a planear una feria del libro. La tabla muestra la lista de precios de cada tipo de libro de la editorial” // “In this activity, you’ll plan a book fair. The table shows the price list of each type of book from the publisher.” • “A veces, cuando planeamos un evento, como una feria del libro, hacemos suposiciones. Las suposiciones son cosas que creemos que van a ser verdaderas basándonos en nuestras experiencias, pero a veces puede que no sean verdaderas. Por ejemplo, podemos hacer suposiciones sobre quiénes podrían venir a la feria del libro” // “Sometimes when we plan something like a book fair, we make assumptions. Assumptions are things we think will be true based on our experiences, but they might not always be. For example, we can make assumptions about who might come to the book fair.” • “¿Quiénes podrían venir a la feria del libro a comprar libros?” // “Who might come to the book fair and buy books?” (students, parents, grandparents, friends) • As you plan the book fair, think about other assumptions you make, how they affect the book fair, and how to communicate them in your work. ### Activity • 1–2 minutes: quiet think time • 10–12 minutes: partner work time • Monitor for students who: • Select the types of books based on the kinds of attendees. For example, they select history books because that is something parents want and chapter books which are preferred by students. • Make assumptions about the number of attendees and the number of each type of book sold. ### Student Facing Lista de precios de la editorial: Planea una feria del libro: tipo de libro precio colecciones \$24.95
cómics \$2.60 libros de ciencias \$8.00
novelas infantiles \$9.99 libros de historia \$14.49
audiolibros \$20.00 libros de actividades \$4.50
libros de consulta \$12.00 libros en español \$6.00
biografías \\$6.05
1. Escoge de 3 a 5 tipos de libros que quieras pedir.
2. Decide qué precio con ganancia le vas a poner a cada tipo de libro que escojas.
3. Estima la cantidad de dinero que se va a recolectar en tu escuela gracias a las ganancias de tu venta de libros.

Escribe una estimación que sea:

muy baja razonable muy alta
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4. Muestra o explica cómo razonaste al hacer la estimación. Incluye las suposiciones que hayas hecho.

### Activity Synthesis

• Invite students to share their book sale plans.
• Invite students to share their assumptions.
• “¿Por qué hicieron estas suposiciones?” // “Why did you make these assumptions?” (There are 600 students, so I thought that maybe only half would come since that is usually what happens. Since the school wants to make a profit, but also make the books affordable, the mark-up price is only one more dollar than the list price.)

## Lesson Synthesis

### Lesson Synthesis

“Hoy planearon una feria del libro e hicieron algunas suposiciones para tomar decisiones” // “Today, you planned a book fair and made assumptions to make decisions about the book fair.”

“¿Cómo influyeron las suposiciones que hicieron en su plan o en el dinero que se recolectó en la feria del libro?” // “How did the assumptions you made affect your plan or the money raised at the book fair?” (I picked the kinds of books to sell based on the people I thought would come. I assumed everyone who came would buy at least one book. I assumed that half of the students from the school would come. This helped me decide how to price the books so we can raise the most money without making the books too expensive.)