Lesson 17

The purpose of this Number Talk is to elicit strategies and understandings students have for adjusting the numbers in an expression to make it easier to find the value. These understandings help students develop fluency.

• 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

• Record answers and strategy.
• Keep expressions and work displayed.
• Repeat with each expression.

• “Cuando cambian un número de una expresión para que sea más fácil, ¿cómo recuerdan que deben modificar los otros números de la expresión?” // “When you change one number in an expression to make it easier, how do you remember how to adjust any other numbers in the expression?”

The purpose of this activity is for students to learn stage 6 of the Target Numbers center. Students add hundreds, tens, and ones to get as close to 1,000 as possible.

Each group of 2 needs 3 number cubes.

• Groups of 2
• Give each group number cubes and two recording sheets.
• “Vamos a aprender una nueva forma de jugar el centro ‘Números objetivo’” // “We are going to learn a new way to play the Target Numbers center.”
• “En esta versión, suman centenas, decenas y unidades para acercarse lo que más puedan a 1,000” //  “In this version, you add hundreds, tens, and ones to get as close to 1,000 as possible.” 
• “Tómense un minuto para leer las instrucciones con su compañero” // “Take a minute to read the directions with your partner.”
• Answer any questions or play a round with the class as needed. 
• “Jueguen esta nueva versión de ‘Números objetivo’ con su compañero” // “Play this new version of Target Numbers with your partner.”

• 10 minutes: partner work time

• “¿Cómo decidieron cuáles de los números que sacaron serían centenas, decenas o unidades?” // “How did you decide which numbers you rolled would be hundreds, tens, or ones?”

The purpose of this activity is for students to learn stage 7 of the Target Numbers center. Students subtract hundreds, tens, and ones to get as close to 0 as possible. Then, students choose from any stage of previously introduced centers.

• Target Numbers
• Five in a Row
• How Close?

• Each group of 2 students needs 3 number cubes.
• Gather materials from:
  • Target Numbers, Stage 6
  • Five in a Row, Stages 7 and 8
  • How Close, Stage 4

• Groups of 2
• Give each group number cubes and two recording sheets.
• “Vamos a aprender una nueva forma de jugar el centro ‘Números objetivo’. En esta versión, restan centenas, decenas y unidades para acercarse lo que más puedan a 0” // “We are going to learn another new way to play the Target Numbers center. In this version, you subtract hundreds, tens, and ones to get as close to 0 as possible.”
• “Tómense un minuto para leer las instrucciones con su compañero” // “Take a minute to read the directions with your partner.”
• Answer any questions.
• “Jueguen esta nueva versión de ‘Números objetivo’ con su compañero” // “Play this new version of Target Numbers with your partner.”

• 10 minutes: partner work time
• “Ahora pueden escoger otro centro. También pueden seguir jugando ‘Números objetivo’” // “Now you can choose another center. You can also continue playing Target Numbers.”
• Display the center choices in the student book.
• Invite students to work at the center of their choice. 
• 10 minutes: center work time
• If time, invite students to choose another center.

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