Lesson 1

The purpose of this warm-up is to elicit the idea that numbers can be broken into parts, which will be useful in upcoming activities. While students may notice and wonder many things about these images, the fact that they have the same number of shapes, but one is separated into 2 parts is the important discussion point.

• Groups of 2
• Display the image.
• “¿Qué observan? ¿Qué se preguntan?” // “What do you notice? What do you wonder?”
• 1 minute: quiet think time

• “Discutan con su pareja lo que pensaron” // “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Share and record responses.

• “¿En qué se parecen estas imágenes? ¿En qué son diferentes?” // “What is the same about these pictures? What is different?” (They both have 5. The first picture is 1 big group but the second picture is 2 groups.)

The purpose of this activity is for students to decompose 6 into 2 parts. Students see that the total number of cubes remains the same when it is decomposed into 2 parts. Although students may notice that they can do this in different ways, that idea is not the focus until the next activity.

• Each student needs 6 connecting cubes.

• Groups of 2
• Give each student 6 connecting cubes.

• “Tienen 6 cubos. Pongan algunos cubos en su mano y algunos en su pupitre” // “You have 6 cubes. Put some of the cubes in your hand and some on your desk.”
• 30 seconds: independent work time
• “Díganle a su pareja cuántos cubos hay en su mano. Muéstrenle los cubos” // “Tell your partner how many cubes are in your hand. Show them the cubes.” 
• “Díganle a su pareja cuántos cubos hay en su pupitre. Muéstrenle los cubos” // “Tell your partner how many cubes are on your desk. Show them the cubes.” 
• “Díganle a su pareja cuántos cubos tienen en total” // “Tell your partner how many cubes you have altogether.”

• Invite a student to share.
• “¿Cuántos cubos tenían en su mano? ¿Cuántos cubos había en su pupitre?” // “How many cubes did you have in your hand? How many cubes were on your desk?”
• Write an expression to represent the parts.
• “¿Cuántos cubos tenían en total?” // “How many cubes did you have in all?” (6)
• “El número total de cubos sigue siendo el mismo cuando los separamos en 2 partes” // “The total number of cubes stays the same when we break them up into 2 parts.”

The purpose of this activity is for students to see that numbers can be decomposed in different ways. Students analyze two different ways that 4 cubes are decomposed into two groups. They determine that although they are decomposed into different-sized parts, they both represent a total of 4.

• Groups of 2
• Give students access to connecting cubes.
• “Diego y Lin también pusieron algunos cubos en sus manos y algunos en sus pupitres. Diego tiene 3 en su mano y 1 en su pupitre. Él dice que tiene 4 cubos en total. Lin tiene 2 en su mano y 2 en su pupitre. También dice que tiene 4 cubos en total. ¿Puede cada uno tener 4 cubos en total?” // “Diego and Lin also put some cubes in their hands and some on their desks. Diego has 3 in his hand and 1 on his desk. He says he has 4 cubes altogether. Lin has 2 in her hand and 2 on her desk. She also says she has 4 cubes total. Can they both have 4 cubes altogether?”

• 3 minutes: partner discussion
• Monitor for students who count the groups to determine that both students have 4 even though they are broken into different parts.

• “¿Diego y Lin tienen 4 cubos cada uno?” // “Do Diego and Lin both have 4 cubes?”
• Invite previously identified students to share.
• “¿En qué partes separó Diego los 4?” // “What parts did Diego break 4 into? (3 and 1)
• Write \(3 + 1\).
• “¿En qué partes separó Lin los 4?” // “What parts did Lin break 4 into?” (2 and 2)
• Write \(2 + 2\).
• “Diego y Lin nos mostraron que podemos separar números de maneras diferentes” // “Diego and Lin showed us that we can break numbers apart in different ways.”

The purpose of this activity is for students to learn stage 1 of the Check It Off center. Students take turns picking two number cards (0–5) to make and find the value of an addition expression. Students check off the total and then write the addition expression on the recording sheet. 

After they participate in the center, students choose from any stage of previously introduced centers.

• Find the Value of Expressions
• Bingo
• Shake and Spill

Students will choose from these centers throughout the section. Keep materials from these centers organized to use each day.

• Gather materials from: 
  • Find the Value of Expressions, Stage 1
  • Bingo, Stages 1–3
  • Shake and Spill, Stages 1–3

• Groups of 2
• Give each group of students a set of number cards and each student a recording sheet.
• “Vamos a conocer un centro nuevo llamado ‘Márcalo’. Por turnos, ustedes y su pareja van escoger dos tarjetas de números. Encuentren el total de los dos números y marquen el total en su hoja de registro. Después, completen una expresión” // “We are going to learn a center called Check It Off. You and your partner will take turns choosing two number cards. Find the total of the two numbers, and check off the total on your recording sheet. Then fill in an expression.”

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

• “Escojan 1 expresión de las que escribieron en su hoja de registro. Cuéntenle a su pareja cómo pueden encontrar el valor de esa expresión” // “Choose 1 expression that you wrote on your recording sheet. Tell your partner how you can find the value of that expression.”