# Lesson 13

Resolvamos nuestros problemas-historia

## Warm-up: Conversación numérica: Formemos una decena (10 minutes)

### Narrative

The purpose of this Number Talk is to elicit strategies and understandings students have for adding within 100. Students may share how they use mental strategies to make a ten. When students share how they use the value of one expression to find the value of the next expression, they look for and express regularity in repeated reasoning (MP8).

### Launch

• Display one expression.
• “Hagan una señal cuando tengan una respuesta y puedan explicar cómo la obtuvieron” // “Give me a signal when you have an answer and can explain how you got it.”
• 1 minute: quiet think time

### Activity

• Record answers and strategies.
• Keep expressions and work displayed.
• Repeat with each expression.

### Student Facing

Encuentra mentalmente el valor de cada expresión.

• $$38 + 7$$
• $$38 + 17$$
• $$38 + 27$$
• $$38 + 57$$

### Activity Synthesis

• “¿Qué cambia en la segunda, en la tercera y en la cuarta suma?” // “What changes in the second, third, and fourth sums?” (the tens of the second number)
• “¿Cómo les ayuda esto a calcular la tercera y la cuarta suma?” // “How does this help you calculate the third and fourth sums?” (I just add some more tens.)

## Activity 1: Resolvamos problemas-historia (20 minutes)

### Narrative

The purpose of this activity is for students to solve their story problems and represent one or more ways to solve the problem (MP2). As students work, encourage them to find a different way to solve the problem or a different way to represent the problem once they have completed a solution.

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• Give students materials to make posters.

### Activity

• “Hoy van a resolver su problema-historia y luego van a hacer un póster que muestre su problema y cómo lo resolvieron” // “Today you are going to solve your story problem and then make a poster that shows your story problem and how you solved it.”
• “Si les queda tiempo, pueden usar imágenes, palabras o símbolos para mostrar distintas maneras de resolver el problema” // “If you have time, you can show different ways to solve the problem using pictures, words, or symbols.”
• 10 minutes: independent work time
• “Compartan su póster con su compañero y hagan ajustes si es necesario” // “Share your poster with your partner and make revisions if needed.”
• 5 minutes: partner discussion

### Student Facing

1. Resuelve el problema-historia que escribiste ayer.

2. Haz un póster de tu problema-historia. Asegúrate de incluir:

• tu historia con la pregunta

• cómo pensaste y cómo razonaste para resolver el problema, usando:

• imágenes
• diagramas
• palabras
• expresiones
• la respuesta a la pregunta de tu problema-historia

### Activity Synthesis

• “En la siguiente actividad, van a ver los pósteres y a dejar comentarios” // “In the next activity, you are going to look at the posters and leave comments.”
• “¿En qué cosas se van a fijar cuando vean los pósteres?” // “What are some things that you will look for when you look at the posters?” (Do I understand the story? Do I agree with the solution? Can I follow the thinking or reasoning?)
• “Mencionen varias maneras en las que se pueden mostrar las soluciones de los problemas” // “What are some different ways you can show solutions to the problems?” (pictures of objects, base-ten pictures, diagrams, number line diagrams, expressions, equations)
• “Préstenle atención a todas estas representaciones y piensen en cuáles escogerían si estuvieran resolviendo el problema” // “Keep an eye out for all of these representations and think about which ones you would choose if you were solving the problem.”

## Activity 2: Recorrido por el salón: Problemas-historia (15 minutes)

### Narrative

The purpose of this activity is for students to see the different story problem posters their classmates made. After the gallery walk, students have a chance to make revisions to their own posters. This could be making corrections, but it could also be adding new details or different representations based on what they learned from seeing the other posters. Some students might need guidance with asking mathematical questions or leaving feedback using precise math language (MP3, MP6).

Consider asking or displaying:

• “Mencionen algo que hayan leído o visto que les haya ayudado a entender el problema-historia” // “What is something you read or saw that helped you understand the story problem?”
• “Mencionen algo que el autor del póster podría agregar o cambiar para hacer que el problema sea más claro” // “What is something the writer could add or change to help make the problem more clear?”
• “Mencionen algo que hayan visto que ayudó a aclarar cómo se resolvió el problema” // “What is something you saw that made it clear how the problem was solved?”
• “Mencionen algo que se puede agregar o cambiar para que el método del autor del póster sea más claro” // “What is something that could be added or changed to make the writer’s method more clear?”
• “¿Qué preguntas tienen sobre el problema-historia o la solución?” // “What questions do you have about the story problem or the solution?”

The goal of the activity synthesis is to reflect on how the posters were the same and how they were different.

MLR7 Compare and Connect. Synthesis: After the Gallery Walk, lead a discussion comparing, contrasting, and connecting the different approaches to solving the problems. Ask, “¿Qué tuvieron en común las estrategias? ¿En qué fueron diferentes?” // “What did the approaches have in common?”, “How were they different?” To amplify student language and illustrate connections, follow along and point to the relevant parts of the displays as students speak.
Engagement: Provide Access by Recruiting Interest. Revisit math community norms to prepare students for the gallery walk. Give examples of appropriate comments and ways to agree or disagree with peers’ work. Be sure students are ready for a whole-class discussion during the lesson synthesis as well.
Supports accessibility for: Social-Emotional Functioning, Attention

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• Display student posters on tables or walls.
• Give students access to sticky notes.

### Activity

• “Caminen por el salón con su compañero y examinen los pósteres. Hablen con su compañero sobre qué observan y qué se preguntan” // “Walk around the room with your partner and look at the posters. Talk to your partner about what you notice and what you wonder.”
• “Usen sus notas adhesivas para dejar comentarios o preguntas sobre las historias y soluciones. Incluyan cosas que les hayan ayudado a entender el problema y las soluciones, y cualquier otra representación que podrían agregar al póster” // “Use your sticky notes to leave comments or questions about the stories and solutions, including things that helped you understand the problem and solutions and any other representations you might add to the poster.”
• 7 minutes: partner work time
• “Ajusten su póster teniendo en cuenta lo que vieron y lo que discutieron” // “Make revisions to your own poster based on what you saw and discussed.”
• 3 minutes: independent work time
• Monitor for students who may need questions or prompts to guide them with leaving feedback.

### Activity Synthesis

• “¿Qué cambiaron en su póster después de ver los otros pósteres?” // “What did you change on your poster after seeing the other posters?” (Answers vary.)
• “Si les queda tiempo, ¿qué otros cambios le harían o qué le agregarían al póster?” // “If you had time, what other changes or additions would you make?”

## Lesson Synthesis

### Lesson Synthesis

“De todo lo que aprendieron en matemáticas este año, ¿de qué están más orgullosos? ¿Qué es lo que más desean aprender en tercer grado?” // “What are you most proud of that you learned in math this year? What are you most looking forward to learning in third grade?”