# Lesson 20

¿Cuál es la historia?

## Warm-up: Cuántos ves: Tablero de 10 (10 minutes)

### Narrative

The purpose of this How Many Do You See is to support students in gaining fluency with sums within 10. In this activity, students have an opportunity to notice and make use of structure (MP7) because they can use the structure of the 10-frame. Students can also determine how many dots they would need to add to fill the 10-frame.

### Launch

• Groups of 2
• “¿Cuántos ven? ¿Cómo lo saben?, ¿qué ven?” // “How many do you see? How do you see them?”
• Flash the image.
• 30 seconds: quiet think time

### Activity

• Display the image.
• “Discutan con su compañero cómo pensaron” // “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Record responses.
• Repeat for each image.

### Student Facing

¿Cuántos ves?
¿Cómo lo sabes?, ¿qué ves?

### Activity Synthesis

• “¿Alguien vio los puntos de la misma forma, pero lo explicaría de otra manera?” // “Did anyone see the dots the same way but would explain it differently?”

## Activity 1: Escribamos problemas-historia (15 minutes)

### Narrative

The purpose of this activity is for students to write story problems based on equations. Students are given equations with boxes for the unknowns. They may choose any two equations. When students write story problems from equations, they reason abstractly and quantitatively (MP2). During the synthesis, students discuss which equation matches the story problem and explain how they know.

MLR7 Compare and Connect. Synthesis: After both groups have presented their thinking, lead a discussion comparing, contrasting, and connecting the different approaches. Ask, “¿En qué se parecen los métodos de las distintas parejas? ¿En qué son diferentes? ¿Ambos métodos funcionan? ¿Por qué?” // “How are the groups’ approaches similar? How are they different? Do both approaches work? Why?”
Engagement: Develop Effort and Persistence. Differentiate the degree of difficulty or complexity. Some students may benefit from starting with a familiar context for a story problem. For example, you may ask some students to use the context from previous lessons.
Supports accessibility for: Conceptual Processing, Attention

• Groups of 2

### Activity

• “Han resuelto y representado diferentes tipos de problemas-historia. Hoy, van a escoger dos ecuaciones y van a escribir un problema-historia para cada ecuación. Pueden escoger las dos ecuaciones que quieran” // “You have solved and represented different types of story problems. Today you will choose two equations and write a story problem for each equation. You may choose any two equations you want.”
• 8–10 minutes: partner work time
• Monitor for 2–3 different story problems to share during the synthesis.

### Student Facing

Escoge 2 ecuaciones. Escribe un problema-historia para cada ecuación.

• $$3 + 5 = \boxed{\phantom{8}}$$
• $$4 + \boxed{\phantom{3}} = 7$$
• $$10 - 5 = \boxed{\phantom{5}}$$
• $$9 = 5 +\boxed{\phantom{4}}$$
• $$\boxed{\phantom{3}} + \boxed{\phantom{7}} = 10$$
• $$6 + \boxed{\phantom{3}} = 9$$
• $$8 = 2 + \boxed{\phantom{6}}$$
1. Ecuación: ________________________________

Problema-historia:

2. Ecuación: ________________________________

Problema-historia:

### Activity Synthesis

• Invite previously identified students to share.
• “¿Cuál ecuación corresponde a la historia que ellos escribieron? ¿Cómo corresponde la ecuación a la historia?” // "Which equation matches the story they wrote? How does it match the story?"

## Activity 2: Tengo la respuesta (10 minutes)

### Narrative

In this activity, students begin by choosing the answer to the problem they will write. They then write an equation that includes that number in any position. Finally, students write a story problem that matches their equation. This builds directly from the previous activity in which students wrote story problems, but has an added layer of complexity as students have to generate their own equations from which to write the story problem. During the launch, students generate equations in which 6 is the answer. This list should be made available to students as they generate their own equations later in the activity. This activity is the second time that students will write story problems, so students may only write story problems for which the number they chose is the result or total.

### Launch

• Groups of 2
• Display $$3 + 3 = 6$$ and $$10 - 6 = 4$$.
• “¿Qué otras ecuaciones podemos escribir que tengan un valor de 6?” // “What are some other equations we can write that have a value of 6?”
• 30 seconds: quiet think time
• Share and record responses.

### Activity

• “Acabamos de escribir problemas-historia que correspondían a las ecuaciones dadas. Ahora van a escribir la ecuación y el problema-historia. Escojan un número. Este número será la respuesta de su problema-historia. Escriban una ecuación con este número como la respuesta. Después, escriban un problema-historia que corresponda a la ecuación que escribieron” // "We just wrote story problems to match given equations. Now you will write the equation and the story problem. You will choose a number. This number will be the answer to your story problem. You will write an equation with this number as the answer. Then write a story problem that matches the equation you wrote."
• 5 minutes: independent work time
• “Compartan su problema-historia y su ecuación con su compañero. Trabajen juntos para asegurarse de que su problema-historia y su ecuación corresponden” // “Share your story problem and equation with your partner. Work together to make sure your story problem and equation match.”
• 4 minutes: partner discussion
• Monitor for story problems with answers in different places to share during the lesson synthesis.

### Student Facing

Marca un número que represente tu respuesta.

2

3

4

5

6

7

8

9

10

Escribe una ecuación que incluya el número que marcaste.
Dibuja un cuadro alrededor del número.

Ecuación: ________________________________

Escribe un problema-historia que corresponda a tu ecuación.

Comparte tu problema-historia con un compañero.
Resuelve el problema-historia de tu compañero.

Escribe la ecuación que corresponde al problema-historia.

Ecuación: ________________________________

### Student Response

If students write story problems with an answer other than the number they circled, consider asking:

• “¿Qué ecuación escribiste con el número que escogiste?” // "What equation did you write with the number you chose?"
• “¿Cómo corresponde esa ecuación a la historia que escribiste?” // "How does that equation match the story you wrote?"

### Activity Synthesis

• “Compartamos algunos problemas-historia y pensemos en ecuaciones que podrían representar a cada uno” // “Let’s share some story problems and think of equations that could represent each one.”

## Activity 3: Centros: Momento de escoger (15 minutes)

### Narrative

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 10. Students choose from any stage of previously introduced centers.

• Capture Squares
• Shake and Spill
• What’s Behind My Back

### Required Materials

Materials to Gather

### Required Preparation

• Gather materials from previous centers:
• Capture Squares, Stages 1 and 2
• Shake and Spill, Stages 3 and 4
• What's Behind My Back, Stage 2

### Launch

• Groups of 2
• “Ahora van a escoger un centro de los que ya conocemos” // “Now you are going to choose from centers we have already learned.”
• Display the center choices in the student book.
• “Piensen qué les gustaría hacer” // “Think about what you would like to do.”
• 30 seconds: quiet think time

### Activity

• Invite students to work at the center of their choice.
• 10 minutes: center work time

### Student Facing

Escoge un centro.

Revuelve y saca

Qué hay a mis espaldas

### Activity Synthesis

• “Clare estaba jugando ‘Qué hay a mis espaldas’ con ocho cubos encajables. Su compañera escondió algunos cubos detrás de su espalda y le mostró tres cubos. Clare contó ‘7, 6, 5’. Ella dijo que su compañera estaba escondiendo cinco cubos. ¿Qué ecuación podemos escribir para mostrar cómo Clare resolvió el problema?” // “Clare was playing What’s Behind My Back with eight connecting cubes. Her partner hid some behind her back and showed her three cubes. Clare counted, ‘7, 6, 5.’ She said her partner was hiding five behind her back. What equation can we write to show how Clare solved the problem?” ($$8 - 3 = \boxed{5}$$)

## Lesson Synthesis

### Lesson Synthesis

Share a previously identified story problem.

“Hoy escribimos nuestros propios problemas-historia. Este es un problema que escribió uno de sus compañeros. ¿Qué ecuaciones corresponden a este problema-historia?” // “Today we wrote our own story problems. This is a problem one of your classmates wrote. What equations match this story problem?”

If needed, ask, “¿En dónde va el cuadro en la ecuación?” // “Where does the box go in the equation?”

If needed, ask, “¿Cómo se puede representar este problema-historia con una ecuación que tenga un valor desconocido?” // “What is an equation with an unknown value that represents this story problem?”

## Student Section Summary

### Student Facing

• Aprendimos sobre ecuaciones en las que faltaba un número y las relacionamos con problemas-historia.

Lin tiene 5 fichas de Bingo en su cartón.
También tiene algunas fichas sobre la mesa.
En total, tiene 9 fichas de Bingo.
¿Cuántas fichas tiene Lin sobre la mesa?

$$9 - 5 = \boxed{\phantom{4}}$$
y
$$5 + \boxed{\phantom{4}} = 9$$

• Pensamos en cómo la suma y la resta están relacionadas mientras resolvíamos problemas-historia en los que sumábamos y restábamos.

9 estudiantes juegan Bingo.
3 estudiantes usan fichas azules para cubrir sus cartones.
Los otros estudiantes usan fichas amarillas.
¿Cuántos estudiantes usan fichas amarillas?

Clare escribió $$3 + \boxed{\phantom{6}} = 9$$
Jada escribió $$9 - 3 = \boxed{\phantom{6}}$$

• Escribimos nuestros propios problemas-historia que correspondían a las ecuaciones.

Intenten escribir una historia que corresponda a estas ecuaciones.

$$7 + 2=\boxed{\phantom{3}}$$
$$6 + \boxed{\phantom{3}}= 9$$