# Lesson 6

Día 1 de centros (optional)

## Warm-up: Conversación numérica: Descompongamos y restemos (10 minutes)

### Narrative

The purpose of this Number Talk is to elicit strategies and understandings students have for decomposing the subtrahend to create a difference that is known or easier to find. These understandings help students develop fluency and will be helpful later in this lesson when students play center games to practice fluency.

### 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

• Keep expressions and work displayed.
• Repeat with each expression.

### Student Facing

Encuentra mentalmente el valor de cada expresión.

• $$65 - 25$$

• $$65 - 27$$

• $$55 - 17$$

• $$46 - 18$$

### Activity Synthesis

• “En algunas de estas estrategias podemos ver que sus compañeros pensaban en descomponer lo que estaban restando para encontrar la diferencia fácilmente. ¿En cuáles?” //  “What strategies did you hear people use that showed thinking about decomposing what you were subtracting to make the difference easier to find?” (I broke the second number into tens and ones. I broke the number into tens and as many ones as I could to take away all the ones. Then I counted back what was left.)

## Activity 1: Conozcamos “Carrera sobre rectas numéricas: Dos, cinco, diez” (15 minutes)

### Narrative

The purpose of this activity is for students to learn stage 1 of the Number Line Scoot center. In this stage, Twos, Fives, and Tens, Students take turns spinning a spinner and moving their cube that interval on one of the shared number lines. Students may use the number they spin to move that number of length units on one number line or decompose the number and move on multiple number lines. Each time a cube lands exactly on the last tick mark of one of the number lines, the player who moved it keeps the cube and puts a new cube on zero on that number line. The first player to collect 5 cubes wins.

The work of this activity builds a foundation for addition on the number line in upcoming lessons.

### Required Materials

Materials to Gather

Materials to Copy

• Number Line Scoot Stage 1 Spinner
• Number Line Scoot Stage 1 Gameboard
• Number Line Scoot Stage 1 Directions, Spanish

### Launch

• Groups of 2
• Give each group a spinner, paper clip, centimeter cubes, a gameboard, and the directions.
• Display spinner and gameboard.
• “En este juego, giran la ruleta y mueven cubos sobre rectas numéricas. Si mueven un cubo directamente hasta el final de una recta numérica, se quedan con ese cubo. Pueden repartir el número que sacaron entre más de una recta numérica” //  “In this game, you spin the spinner and move cubes along the number lines. If you are the one to move a cube directly on the end of a number line you get to keep that cube. You can split your spin between more than one number line.”
• “Lean las instrucciones con su compañero” // “Read the directions with your partner.”
• Answer any questions or demonstrate the game for the class if needed.

### Activity

• 8 minutes: partner work time

### Activity Synthesis

• Display a gameboard with several cubes close to the end of some number lines. Then spin the spinner.
• “Este es mi tablero de juego y este es el número que saqué. Ya que tengo que llegar exactamente al final de la recta numérica para quedarme con un cubo, ¿qué jugada harían en el tablero?” // “This is my gameboard and my next spin. Since I have to land exactly on the end of the number line to collect a cube, what move would you make on the gameboard?”

## Activity 2: Centros: Momento de escoger (25 minutes)

### Narrative

The purpose of this activity is for students to choose from activities that focus on addition or subtraction.

Students choose from any stage of previously introduced centers.

• Capture Squares
• Number Line Scoot
• Number Puzzles

### Required Materials

Materials to Gather

### Required Preparation

Gather materials from:

• Capture Squares, Stages 3 and 4
• Number Line Scoot, Stage 1
• Number Puzzles, Stage 4

### Launch

• “Ahora van a escoger centros de los que ya conocemos. Una de las opciones es seguir jugando ‘Carrera sobre rectas numéricas’” // “Now you will choose from centers we have already learned. One of the choices is to continue with Number Line Scoot.”
• 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.
• 10 minutes: center work time
• “Escojan qué les gustaría hacer ahora” // “Choose what you would like to do next.”
• 10 minutes: center work time

### Student Facing

Escoge un centro.

Carrera sobre rectas numéricas

Acertijos numéricos

### Activity Synthesis

• “¿Qué les gustó de las actividades en las que trabajaron hoy?” // “What did you like about the activities you worked on today?”

## Lesson Synthesis

### Lesson Synthesis

“En nuestras actividades de los centros de hoy teníamos que sumar y restar. ¿Qué estrategia usaron como ayuda para sumar y restar?” // “Today our center activities required us to add and subtract. What strategy did you use to help you add and subtract?”