# Lesson 1

Sumemos y restemos hasta 10

## Warm-up: ¿Qué saben sobre las matemáticas? (15 minutes)

### Narrative

The purpose of this activity is to elicit ideas students have about doing math. Students learn the What Do You Know _____? routine which will be used throughout the year. This routine provides an opportunity for all students to contribute to the conversation and for the teacher to listen to what knowledge students already have. Since this is the first warm-up of the year, we allocated 15 minutes, instead of 10, to establish the structure of a routine.

For all of the routines, consider establishing a small, discreet hand signal that students can display to indicate they have an answer they can support with reasoning. This signal could be a thumbs-up, a certain number of fingers that tells the number of responses they have, or another subtle signal. This is a quick way to see if students have had enough time to think about the problem. It also keeps students from being distracted or rushed by hands being raised around the class.

### Launch

• Display the question.
• “¿Qué saben sobre las matemáticas?” // “What do you know about math?”
• 1 minute: quiet think time

### Activity

• Record responses.

### Student Facing

¿Qué sabes sobre las matemáticas?

### Activity Synthesis

• “Hoy, ustedes harán matemáticas de varias maneras” // “Today, you will get to do math in different ways.”

## Activity 1: Márcalo: Suma y resta hasta 10 (20 minutes)

### Narrative

The purpose of this activity is for students to demonstrate methods they have for addition and subtraction within 10. In this activity, students draw 2 cards and consider how they could add or subtract the numbers to create a value that matches one of the target numbers (010). Listen for the ways students think about how to find the value of sums and differences, including any sums and differences they know from memory, and how they share their thinking with their partner. If students disagree about the value of a sum or difference, encourage them to discuss their reasoning and reach an agreement (MP3).

Students may write subtraction expressions that do not match their computation (for example, students write $$2 - 4$$ instead of $$4 - 2$$). Ask them to use counters or cubes to represent the subtraction. Highlight that they started with 4 and took away 2 and ask them to connect this action to the expression. To stay mathematically consistent with what students will learn in later grades about operations with rational numbers, avoid language that suggests students can only subtract a smaller number from a larger number.

MLR8 Discussion Supports. Provide all students with an opportunity for verbal output. Invite students to read each expression they create to their partner. Amplify words and phrases such as: add, addition, sum, take away, difference, value, and expression.
Representation: Access for Perception. Some students may benefit from a demonstration of how to play the game using the available connecting cubes or counters.
Supports accessibility for: Conceptual Processing, Visual-Spatial Processing

### Required Materials

Materials to Gather

Materials to Copy

• Number Cards (0-10)

### Required Preparation

• Create a set of number cards for each group of 2.
• The number cards will be used in upcoming lessons and thoughout the year. Consider copying the cards on cardstock or laminating them for future use.
• Create the math community poster for display in the lesson synthesis.

### Launch

• Groups of 2
• Give each group a set of number cards.
• “Vamos a jugar ‘Márcalo: Suma y resta hasta 10’. El objetivo es ser la primera persona en escribir una expresión para cada número” // “We are going to play Check It Off: Add or Subtract within 10. The goal is to be the first person to write an expression for each number.”
• “Voy a escoger dos tarjetas (Show 10 and 7). Tengo que decidir si quiero sumar o restar. No quiero un valor mayor que 10, así que voy a restar” // “I’m going to pick two cards. (Show 10 and 7.) I have to decide whether I want to add or subtract. I don’t want a value greater than 10, so I’m going to subtract.”
• Write $$10 - 7$$.
• “¿Cuál es el valor de la diferencia?” // “What is the value of the difference?”
• 30 seconds: quiet think time
• Share responses.
• “Anoto en mi hoja de registro la expresión que hice al lado del valor de la diferencia y marco el número. Ahora es el turno de mi pareja” // “I record the expression I made on my recording sheet next to the value of the difference and check off the number. Now it’s my partner’s turn.“
• “Por turnos, escojan tarjetas, hagan una expresión de suma o resta, encuentren el valor de la suma o la diferencia y muéstrenle a su pareja cómo lo supieron” // “Take turns picking cards, making an addition or subtraction expression, finding the value of the sum or difference, and showing your partner how you know.”
• “Si se les acaban las tarjetas antes de que alguien marque todos los números, barájenlas y empiecen de nuevo” // “If you run out of cards before someone checks off all the numbers, shuffle them and start again.“

### Activity

• 1015 minutes: partner work time

### Student Facing

1. Escoge 2 tarjetas y encuentra el valor de la suma o la diferencia.
2. Marca el número que encontraste y escribe la expresión.
3. La primera persona que marque todos los números gana.
¡Lo encontré!                      Expresión
0
1
2
3
4
5
6
7
8
9
10

### Activity Synthesis

• “¿Escribieron algunas expresiones que correspondieran al mismo valor? ¿Qué número era? ¿Cuáles eran las expresiones?” // “Did you write any expressions that matched the same value? What number was it? What were the expressions?"
• “¿Hubo algunos valores que ustedes y su pareja no encontraron? ¿Qué expresiones pueden corresponder a estos números?” // "Were there any values that you and your partner did not find? What are some expressions that could match these numbers?"
• “¿Qué expresiones obtuvieron para 5?” // “What expressions did you get for 5?” (Answers will vary. Sample response: I found $$10 - 5$$ and  $$3 + 2$$.)
• “¿Qué expresiones obtuvieron para 0?” // “What expressions did you get for 0?” (Answers will vary. Sample response: I found $$9 - 9$$ and $$0 + 0$$.)
• “¿Qué expresiones obtuvieron para 10?” // “What expressions did you get for 10?” (Answers will vary. Sample response: I found $$3 + 7$$ and $$10 + 0$$.)

## Activity 2: ¿Cuál es el valor? (10 minutes)

### Narrative

The purpose of the activity is for students to practice finding the value of sums and differences within 10. Students also identify addition expressions that have a value of 10. Students will work more with sums of 10 in the next lesson. This activity provides an opportunity to observe how students find sums and differences within 10, including those they know from memory.

### Required Materials

Materials to Gather

• Groups of 2

### Activity

• 6 minutes: independent work time
• “Compartan con un compañero lo que pensaron y sus respuestas” // “Share your thinking and your answers with a partner.”
• 1 minute: partner discussion

### Student Facing

1. Empareja cada expresión con el valor de la suma o la diferencia.

• $$5 + 3$$
• $$3 - 1$$
• $$10 - 1$$
• $$4 + 5$$
• $$6 + 3$$
• $$6 - 5$$
• $$1 + 6$$
• $$9 - 5$$
• $$8 - 5$$
• $$3 + 6$$
• 9
• 3
• 8
• 7
• 1
• 4
• 2
2. Marca todas las expresiones de suma que tengan un valor de 10.
3. ¿Qué patrones ves en los números de las expresiones que tienen un valor de 10?

### Activity Synthesis

• Record responses.

## Lesson Synthesis

### Lesson Synthesis

“Hoy jugaron un juego matemático y sumaron y restaron hasta 10. Vamos a hacer un póster para describir lo que ustedes y yo hacemos en nuestra comunidad matemática” // “Today, you played a math game and added and subtracted within 10. We are going to make a chart to describe what you do and I do in our mathematical community.”

Display math community poster.

“¿Qué ven y qué escuchan cuando hacemos matemáticas juntos como una comunidad matemática?” // “What does it look and sound like to do math together as a mathematical community?”  (We talked to each other and to the teacher. We had some quiet time to think. We shared our ideas. We thought about the math ideas and words we knew. You were writing down our answers. You were waiting until we gave the answers.)

Share and record responses.