# Lesson 15

Expliquemos cómo contamos

## Warm-up: Preguntas sobre nosotros: Representemos la asistencia (parte 2) (10 minutes)

### Narrative

The purpose of this warm-up is for students to experience part of the Questions About Us routine. Students continue to engage in this routine throughout the section, focused on answering, “¿Cuántos estamos hoy aquí?” // “How many of us are here today?” In this activity, students develop ideas for how to represent how many students are here today. Student ideas should drive which representation is created. Save the poster from this warm-up for comparison in the next lesson. As students observe that counting their classmates and counting a representation of their classmates give the same result, they are building an understanding of how numbers represent how many there are in a collection (MP2).

### Required Materials

Materials to Gather

### Launch

• Display a blank poster.
• “¿Cómo podemos mostrar cuántos estamos hoy aquí?” // “How can we show how many of us are here today?”
• 30 seconds: quiet think time
• 30 seconds: partner discussion
• Share responses.
• Monitor for students who suggest drawing a stick figure of each student or writing each student’s name.
• Choose one student suggestion and demonstrate representing each student. Represent each student in a way that is different than yesterday.

### Activity

• “¿Cómo podemos descifrar cuántos estamos hoy aquí?” // “How can we figure out how many of us are here?” (We can count each person. We can count each stick figure or name.)
• Count each student.
• “¿Cuántos estamos hoy aquí?” // “How many of us are here today?”
• Count each name or stick figure.
• “¿Cuántos estamos hoy aquí?” // “How many of us are here today?”

### Activity Synthesis

• “¿Qué hicimos para mostrar a cada estudiante de nuestra clase?” // “What did we do to show each student in our class?”

## Activity 1: Contemos colecciones: Comparte cómo contaste (15 minutes)

### Narrative

The purpose of this activity is for students to count their collection in a way that makes sense to them and share how they counted with a partner. Sharing how many objects are in the collection and how they counted will be useful when students represent their count in the next lesson. Most students should be given collections with 6–10 objects. Based on formative assessment data collected in previous sections, adjust the number of objects in collections for individual students. Students are provided with counting mats and 5-frames to help them accurately count or organize their collections. Students use appropriate tools strategically as they choose which tools help them count their collections (MP5).

Additional collections can be provided to allow students to choose a new collection to count.

MLR8 Discussion Supports. Provide multiple opportunities for verbal output. Invite students to chorally repeat each count in unison.

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• “Hoy van a contar otra colección de objetos” // “Today you’re going to count another collection of objects.”

### Activity

• Give each student a bag of objects. Give students access to 5-frames and a counting mat.
• “Descubran cuántos objetos hay en su colección” // “Figure out how many objects are in your collection."
• 2 minutes: independent work time
• “Intercambien colecciones con un compañero. Descubran cuántos objetos hay en su nueva colección” // “Switch collections with a partner. Figure out how many objects are in your new collection.”
• 2 minutes: independent work time
• “Cuéntenle a su compañero cuántos objetos hay en su colección. Muéstrenle cómo contaron los objetos” // “Tell your partner how many objects are in your collection. Show them how you counted the objects.”
• 30 seconds: quiet think time
• 2 minutes: partner discussion
• Monitor for students who demonstrate how they used a counting mat or 5-frame to count their objects.

### Activity Synthesis

• Invite previously identified students to share how they counted their collections.
• “¿Cómo les ayudo el tablero de 5 (o el tablero de conteo) a contar su colección de objetos?” // “How did the 5-frame (or counting mat) help you count your collection of objects?”
• After each student shares, write or display the number and say, “Hay _____ objetos en su colección” // “There are _____ objects in their collection.”

## Activity 2: Usemos un tablero de conteo para llevar la cuenta [OPTIONAL] (10 minutes)

### Narrative

The purpose of this optional activity is for students to use a counting mat as a tool to help them keep track of which objects have been counted. Based on formative assessment data from previous sections and observation during the first activity, this activity will be helpful for students who are not counting all objects or counting some objects more than one time.

This activity also serves as further formative assessment on students’ counting concepts, including one-to-one matching and understanding that the last number tells us “how many.”

This activity can be used with a small group or the whole class. Students who do not need this optional activity may benefit from additional time working in centers.

Representation: Internalize Comprehension. Synthesis: Make connections between the location of the objects on the counting mat. For example, restate that when an object is on one side of the mat it has not been counted and when it is on the other side it has been counted.
Supports accessibility for: Conceptual Processing, Organization

### Required Materials

Materials to Gather

### Launch

• Display a counting mat and a collection of 6–10 objects.
• “¿Cómo nos puede ayudar el tablero de conteo a estar seguros de que contamos cada objeto 1 vez?” // “How can the counting mat help us make sure that we count each object 1 time?”
• 30 seconds: quiet think time
• Share responses.

### Activity

• Give each student a collection of 6–10 objects and a counting mat.
• “Usen el tablero de conteo para descubrir cuántos objetos hay en su colección” // “Use the counting mat to figure out how many objects are in your collection.”
• 2 minutes: independent work time
• As students count, monitor for students who move each object from one side of the counting mat as they say one number.

### Activity Synthesis

• Invite previously identified students to share how they counted.
• Display a collection of 6 objects on one side of a counting mat. Demonstrate counting and moving 4 of the objects to the other side of the counting mat.
• “¿Cuáles objetos me falta contar? ¿Cuáles objetos ya conté? ¿Cómo lo saben?” // “Which objects do I still need to count? Which objects did I already count? How do you know?”

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

### Narrative

The purpose of this activity is for students to choose from activities that focus on using math tools. Students choose from any stage of previously introduced centers.

• Connecting Cubes
• Pattern Blocks
• Geoblocks
• Picture Books

### Required Materials

Materials to Gather

### Required Preparation

• Gather materials from:
• Connecting Cubes, Stages 1, 2, and 3
• Pattern Blocks, Stages 1, 2, and 3
• Geoblocks, Stages 1 and 2
• Picture Books, Stages 1 and 2

### 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 quieren hacer ahora” // “Choose what you would like to do next.”
• 8 minutes: center work time

### Student Facing

Escoge un centro.

Bloques sólidos
geométricos

Cubos encajables

Fichas geométricas

Libros de imágenes

### Activity Synthesis

• “Comenten sobre algún momento en el que algo fue difícil para ustedes cuando trabajaron en los centros. ¿Qué hicieron? // “Tell us about a time when something was challenging for you during centers. What did you do?”

## Lesson Synthesis

### Lesson Synthesis

“Hoy contamos colecciones de objetos. ¿Usaron herramientas matemáticas que les ayudaran a contar? ¿Cómo les ayudaron a contar estas herramientas? // “Today we counted collections of objects. Did you use any math tools to help you count? How did they help you count?”