Lesson 12

Comparemos problemas-historia de suma y de resta

Warm-up: Conteo grupal: Contemos hasta 40 (10 minutes)

Narrative

The purpose of this warm-up is for students to practice saying the verbal count sequence to 40. Students also see the numbers written as they say each number.

Launch

• “Contemos hasta 40” // “Let’s count to 40.”

Activity

• Count to 40 together.
• Record as students count.
• Count to 40 1–2 times. Point to the numbers as students count.

Student Response

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Activity Synthesis

• “¿Cuál número sigue cuando cuento 4, 5, 6, 7...?” // “What number comes next when I count? 4, 5, 6, 7...”
• “¿Cuál número sigue cuando cuento 12, 13, 14, 15...?” // “What number comes next when I count? 12, 13, 14, 15...”
• “¿Cuál número sigue cuando cuento 16, 17, 18, 19...?” // “What number comes next when I count? 16, 17, 18, 19...”

Activity 1: Patos en el estanque (10 minutes)

Narrative

The purpose of this activity is for students to solve an Add To, Result Unknown story problem. In the next activity, students will compare this story problem and a Take From, Result Unknown story problem with the same context. Students have seen expressions in previous lessons, but this is the first time that students are introduced to the term expression.

Representation: Develop Language and Symbols. Synthesis: Use different colors to represent the 5 ducks that start in the pond and the 4 more that come to swim in the pond. Connect the context with the counters and the expression.
Supports accessibility for: Conceptual Processing

Launch

• Groups of 2
• Give students access to connecting cubes or counters.
• “Pueden encontrar muchas plantas y animales diferentes en los parques. ¿Qué tipo de plantas o de animales han visto en su comunidad?” // “You can find many different plants and animals in parks. What kind of plants or animals have you seen in your community?”
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.
• Display the image.
• “Esta imagen es del Parque Audubon en Nueva Orleans. ¿En qué se parece este parque a otros parques en los que han estado? ¿En qué es diferente?” // “This picture is from Audubon Park in New Orleans. How is this park the same as other parks you have been to? How is it different?”
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.
• Read the task statement.
• “Cuéntenle a su compañero lo que ocurrió en la historia” // “Tell your partner what happened in the story.”
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Monitor for students who accurately retell the story. Choose at least one student to share with the class.
• Reread the task statement.
• “Muestren cómo pensaron. Usen dibujos, números, palabras u objetos” // “Show your thinking using drawings, numbers, words, or objects.”

Activity

• 3 minutes: independent work time
• 2 minutes: partner discussion

Student Facing

Había 5 patos en el estanque.

4 patos más llegaron al estanque a nadar.

¿Cuántos patos hay en el estanque ahora?

Student Response

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Advancing Student Thinking

If students draw very detailed drawings, consider asking:

• “Cuéntame más sobre tu dibujo. ¿Cómo decidiste cómo mostrar lo que ocurrió en el problema-historia?” // “Tell me more about your drawing. How did you decide how to show what happened in the story problem?”
• “¿Puedes hacer un dibujo que muestre lo que ocurre en la historia sin tener que dibujar los patos?” // “Can you draw a picture to show what happens in the story without drawing the actual ducks?”

Activity Synthesis

• Invite a student who showed which ducks were in the pond first and which ducks came to the pond to share.
• “Había 5 patos en el estanque. 4 patos más llegaron a nadar en el estanque. Podemos escribir eso como ‘5 y 4’ o ‘$$5 + 4$$’. Cuando escribimos $$5 + 4$$, eso se llama una expresión” // “There were 5 ducks in the pond and then 4 more ducks came to swim in the pond. We can write that as ‘5 and 4’ or ‘$$5 + 4$$’. When we write $$5 + 4$$, it is called an expression.”

Activity 2: Los patos nadan hacia la orilla (10 minutes)

Narrative

The purpose of this activity is for students to solve a Take From, Result Unknown story problem with the same context as the Add To, Result Unknown story problem in the previous activity. The numbers in the two problems are the same. What has changed is the action—that is, instead of 4 ducks joining a group of 5, 4 ducks leave the larger group of 9.

MLR8 Discussion Supports. Some students may benefit from the opportunity to act out or use objects to represent the scenario. Listen for and clarify any questions about the context.
Advances: Speaking, Representing

Launch

• Groups of 2
• Give students access to connecting cubes or counters.
• Read the task statement.
• Reread the story problem from the first activity.
• “¿En qué se parecen los problemas-historia? ¿En qué son diferentes?” // “What is the same about the story problems? What is different about them?” (They are both about ducks in the pond. They are different because in the first one, more ducks came to swim in the pond, and in the second one, some of the ducks left the pond.)
• 30 seconds: quiet think time
• 2 minutes: partner discussion
• Share responses.
• Reread the task statement.
• “Muestren cómo pensaron. Usen dibujos, números, palabras u objetos” // “Show your thinking using drawings, numbers, words, or objects.”

Activity

• 3 minutes: quiet think time
• 2 minutes: partner discussion

Student Facing

Había 9 patos nadando en el estanque.

Luego, 4 de los patos caminaron hacia el césped.

¿Cuántos patos están nadando en el estanque ahora?

Student Response

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Advancing Student Thinking

If students draw pictures or symbols that are scattered, consider asking:

• “¿Puedes usar tu dibujo para contarme lo que ocurrió en el problema-historia?” // “Can you use your drawing to tell me what happened in the story problem?”
• “¿En qué parte de tu dibujo están los patos que estaban nadando en el estanque? ¿Cómo lo sabes? ¿En qué parte de tu dibujo están los patos que caminaron en el césped?” // “Where are the ducks who were swimming in the pond in your drawing? How do you know? Where are the ducks who waddled onto the grass in your drawing?”

Activity Synthesis

• Invite a student to share their representations.
• “Había 9 patos nadando en el estanque. Luego, 4 de los patos caminaron en el césped. Podemos escribir esto como ‘9 quitando 4’ o ‘$$9 - 4$$’. Cuando escribimos $$9 - 4$$, eso se llama una expression” // “There were 9 ducks swimming in the pond and then 4 of the ducks waddled onto the grass. We can write that as ‘9 take away 4’ or ‘$$9 - 4$$’. When we write $$9 - 4$$, it is called an expression.”

Activity 3: Centros: Momento de escoger (20 minutes)

Narrative

The purpose of this activity is for students to choose from activities that offer practice with addition and subtraction, as well as describing and building shapes. Students choose from any stage of previously introduced centers.

• Bingo
• Math Fingers
• Subtraction Towers
• 5-frames
• Math Stories
• Counting Collections

Required Materials

Materials to Gather

Required Preparation

• Gather materials from:
• Bingo, Stages 1-3
• Math Fingers, Stages 1-3
• Math Stories, Stages 1 and 2
• Subtraction Towers, Stage 1
• 5-frames, Stages 1 and 2
• Counting Collections, Stage 1

Launch

• “Hoy vamos a escoger centros de los que ya conocemos” // “Today we are going to choose from centers we have already learned.”
• Display the center choices in the student book.
• “Piensen qué les gustaría hacer primero” // “Think about what you would like to do first.”
• 30 seconds: quiet think time

Activity

• Invite students to work at the center of their choice.
• 8 minutes: center work time
• “Escojan qué les gustaría hacer ahora” // “Choose what you would like to do next.”
• 8 minutes: center work time

Student Facing

Escoge un centro.

Bingo

Dedos matemáticos

Torres para restar

Tableros de 5

Historias matemáticas

Contar colecciones

Activity Synthesis

• “¿Cuáles son sus materiales favoritos para trabajar en los centros?” // “What are your favorite materials to use during center time?”

Lesson Synthesis

Lesson Synthesis

Read the story problem:

There were 5 ducks in the pond.
4 more ducks came to the pond to swim.
How many ducks are in the pond now?

Draw this representation (or display a student representation).

Read the story problem from the second activity and draw this representation (or a similar student representation).

“¿En qué se parecen los dibujos?” // “How are the drawings the same?” (Both have 9 circles. There is a group of 5 in both. There is a group of 4 in both.)

“¿En qué son diferentes los dibujos?” // “How are the drawings different?” (In the second drawing, the group of 4 circles is crossed out.)

Write $$5 + 4$$.

“Había 5 patos en el estanque. Luego, 4 patos más llegaron a nadar en el estanque. El primer dibujo muestra 5 más 4” // “There were 5 ducks in the pond and then 4 more ducks came to swim in the pond. The first drawing shows 5 plus 4.”

Invite students to chorally repeat “5 más 4” // “5 plus 4” 1–2 times.

Write “$$9 - 4$$.”

“Había 9 patos nadando en el estanque. Luego, 4 de los patos se fueron a caminar sobre el césped. El segundo dibujo muestra 9 menos 4” // “There were 9 ducks swimming in the pond and then 4 of the ducks waddled onto the grass. The second drawing shows 9 minus 4.”

Invite students to chorally repeat “9 menos 4” // “9 minus 4” 1–2 times.

Cool-down: Unidad 4, punto de chequeo de la sección B (0 minutes)

Cool-Down

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Student Section Summary

Student Facing

En esta sección aprendimos sobre problemas-historia.
Actuamos problemas-historia. Usamos tanto objetos como dibujos para mostrar lo que pasaba en los problemas-historia y para ayudarnos a resolverlos.

Algunas veces se agregaban cosas en los problemas-historia.

Había 5 patos en el estanque.
4 patos más llegaron al estanque a nadar.
¿Cuántos patos hay en el estanque ahora?

Algunas veces se restaban, o quitaban, cosas en los problemas-historia.

Había 5 balones en el patio de recreo.
Diego llevó 5 de los balones para adentro.
¿Cuántos balones hay en el patio de recreo ahora?