# Lesson 2

Exploremos expresiones y sumas

## Warm-up: Conteo grupal: Contemos hasta 41 (10 minutes)

### Narrative

The purpose of this Choral Count is to invite students to practice counting by 1 and notice patterns in the count. These understandings help students develop fluency with the count sequence and will be helpful as students relate counting to addition and subtraction.

### Launch

• “Cuenten de 1 en 1, empezando en 0” // “Count by 1, starting at 0.”
• Record as students count.
• Stop counting and recording at 41.

### Activity

• “¿Qué patrones ven?” // “What patterns do you see?”
• 1–2 minutes: quiet think time
• Record responses.

### Activity Synthesis

• “¿Alguien quiere compartir otra observación sobre por qué ocurre ese patrón aquí?” // “Does anyone want to add an observation on why that pattern is happening here?”
• “¿Están de acuerdo o en desacuerdo? ¿Por qué?” // “Do you agree or disagree? Why?”

## Activity 1: Emparejemos expresiones con tarjetas de puntos (15 minutes)

### Narrative

The purpose of this activity is for students to relate dot images to addition expressions. In a previous activity, students discussed using addition expressions to show putting together the value of each dot cube. In this activity, students match expressions to dot images and find the total, either by using the dots in the image, or by finding the value of the expression. Students then create matching dot images and expressions by completing the missing component. When students match dot images and expressions and write expressions to match dot images, they reason abstractly and quantitatively (MP2).

• Groups of 2

### Activity

• “En esta actividad, dibujen una línea para emparejar cada imagen de puntos con la expresión que le corresponda. Después, encuentren el total. En la segunda página, completen las expresiones que faltan o las imágenes de puntos que faltan” // “In this activity, draw a line to connect each dot image to its matching expression. Then, find the total. On the second page, complete the missing expressions or the missing dot images.”
• 5 minutes: independent work time
• “Compartan su trabajo con su pareja” // “Share your work with your partner.”
• 3 minutes: partner discussion

### Student Facing

Empareja cada pareja de puntos con una expresión. Después, encuentra el total.

expresión total
$$3+2$$
$$4+2$$
$$5+3$$
$$6+4$$
$$4+3$$

Dibuja los puntos que faltan para que el dibujo corresponda a la expresión. Después, encuentra el total.

Expresión: $$4+2$$

Total: ____________

​​​​​​Expresión: $$5+2$$

Total: ____________

Expresión: $$2+6$$

Total: ____________

Escribe la expresión que falta para que corresponda a los puntos. Después, encuentra el total.

Expresión: _____________________

Total: ____________

Expresión: _____________________

Total: ____________

### Activity Synthesis

• “¿Cómo sabían cuál expresión correspondía a cada grupo de puntos?” // “How did you know which expression matched each set of dots?” (I counted the dots on the first dot cube and wrote the number underneath, then counted the dots on the second one and found the right expression. I knew the first one was four because it looked like a dot cube and then I counted the second one and then found the matching expression.)

## Activity 2: Conozcamos “Márcalo: Suma hasta 10” (20 minutes)

### Narrative

The purpose of this activity is for students to learn a new center called Check it Off, Add within 10. In this activity, students are introduced to the term sum. They find the sum of two numbers in a way that makes sense to them and write addition expressions to represent the sum. Students choose two number cards in order to make each expression. Dot cubes can be used instead of number cards if students would benefit from being able to count the dots in order to find the total. If working with number cards, students may find the sum in any way that makes sense to them, such as using objects, fingers, drawings, or known facts.

Number Cards are provided as a blackline master. Students will continue to use these throughout the year. Consider copying them on cardstock or laminating them and keeping them organized to be used repeatedly.

MLR8 Discussion Supports. To give all students an opportunity for verbal output, and to support the transfer of new vocabulary to long-term memory, invite students to chorally repeat phrases that include the term, “sum” in unison, 1–2 times. For example, “La suma de 1 y 3 es 4” // “The sum of 1 and 3 is 4.”
Engagement: Internalize Self-regulation. Provide students an opportunity to self assess and reflect on their own progress. For example, check in with students, and invite them to share their thinking.
Supports accessibility for: Social-Emotional Functioning, Conceptual Processing

### Required Materials

Materials to Gather

Materials to Copy

• Check It Off Stage 1 Recording Sheet Grade 1, Spanish
• Number Cards (0-10)

### Required Preparation

• Create a set of cards from the blackline master for each group of 2.

### Launch

• Groups of 2
• Give each group a set of cards, two recording sheets, and access to 10-frames and two-color counters.
• “Vamos a conocer un juego llamado ‘Márcalo’. Juguemos una ronda juntos” // “We are going to learn a game called Check It Off. Let’s play a round together.”
• “Primero saquemos todas las tarjetas mayores que cinco. No usaremos esas tarjetas en este juego. Ahora voy a escoger dos tarjetas de números y encontrar la suma de los números. Llamamos suma al total que se obtiene cuando se suman dos o más números” // “First we take out all of the cards greater than five. We will not use those cards in this game. Now I am going to pick two number cards and find the sum of the numbers. The sum is the total when adding two or more numbers.”
• Choose two cards.
• “¿Cuál es la suma de los números?, ¿cómo lo saben?” // “What is the sum of the numbers? How do you know?”
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.
• “Ahora marco la suma. ¿Qué expresión de suma representa la suma de los números?” // “Now I check off the sum. What addition expression represents the sum of the numbers?”
• 30 seconds: quiet think time
• Share responses.
• “Escribo la expresión en mi hoja de registro al lado de la suma. Ahora es el turno de mi pareja” // “I record the expression on my recording sheet next to the sum. Now it’s my partner’s turn.”

### Activity

• “Jueguen por turnos a elegir las dos tarjetas, encontrar la suma y escribir una expresión de suma. Pueden escribir más de una expresión para cada suma” // “Take turns choosing two cards, finding the sum, and writing an addition expression. You may have more than one expression for each sum.“
• 10 minutes: partner work time
• “¿Cómo encontraron la suma?” // “How did you find the sum?”
• “¿Qué expresión escribieron? ¿Qué muestra la expresión?” // “What expression did you write? What does the expression show?”
• Monitor for students who draw pictures or use fingers to find sums.

### Activity Synthesis

• Display number cards 4 and 3.
• “¿Cómo podemos encontrar la suma de estos números?” // "How can we find the sum of these numbers?"
• Invite previously identified students to share.
• “¿Qué expresión de suma podemos escribir para representar la suma de estos números?” // "What addition expression can we write to represent the sum of these numbers?" ($$4 + 3 = 7$$ or $$3 + 4 = 7$$)

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