Lesson 10

The purpose of this Choral Count is to invite students to practice counting by 10 and notice patterns in the count. These understandings help students develop fluency with the count sequence. When students notice the pattern in the ones place as they count by 10, they are looking for and making use of structure (MP7).

• “Contemos de 10 en 10, empezando en 0” // “Count by 10, starting at 0.”
• Record as students count.
• Stop counting and recording at 100.

• “¿Qué patrones ven?” // “What patterns do you see?”
• 1–2 minutes: quiet think time
• Record responses.

• “¿En qué se parecen contar de 10 en 10 y contar de 1 en 1?” // “How is counting by 10 like counting by 1?”
• Consider asking: 
  • “¿Quién puede describir el patrón con otras palabras?” // “Who can restate the pattern in different words?”
  • “¿Alguien quiere compartir otra observación sobre por qué ocurre ese patrón aquí?” // “Does anyone want to add an observation on why that pattern is happening here?”
  • “¿Están de acuerdo o en desacuerdo? ¿Por qué?” // “Do you agree or disagree? Why?”

The purpose of this activity is for students to revisit a center from kindergarten. In this center, What’s Behind My Back, students find the missing part to make 10. They record different ways to make 10 with equations. 

• Each group of 2 needs 10 connecting cubes.

• Groups of 2
• Give each group two recording sheets, ten connecting cubes, and access to 10-frames and two-color counters. 
• “Vamos a jugar un juego que aprendieron en kínder, se llama 'Qué hay a mis espaldas'. Juguemos la primera ronda juntos para asegurarnos de que todos recuerdan cómo se juega” // “We are going to play a game you learned in kindergarten called What’s Behind My Back. Let’s play the first round together to make sure we all remember how to play.”
• Demonstrate starting with a tower of ten cubes. 
• “Cada grupo comienza con una torre de 10 cubos. Luego, un compañero separa la torre en dos partes y esconde una de ellas a sus espaldas” // “Each group will start with a tower of ten cubes. Then one partner will break the tower into two parts and hide one of the parts behind their back.”
• Break the tower into two parts and hide one part behind your back. Show the other part to the class.
• “El otro compañero escribe una ecuación con un cuadro en blanco para representar el número desconocido” // “The other partner will write an equation leaving a blank box for the missing number.”
• Demonstrate writing \(4 + \boxed{\phantom{\frac{aaai}{aaai}}} = 10\).
• “Luego, descifra cuántos cubos están escondidos a las espaldas de su compañero. Pueden usar tableros de 10 y fichas de dos colores si esto ayuda. ¿Cuántos cubos hay a mis espaldas?” // “Then they will figure out how many cubes are hidden behind their partner’s back. You may use 10-frames and two-color counters if they are helpful. How many cubes are behind my back?”
• Share responses.
• “Cuando lleguen a un acuerdo sobre cuántas torres están escondidas, pueden completar la ecuación” // “When you agree on how many are hiding, you can complete the equation.”
• Demonstrate filling in the missing number in the equation. 

• “Ahora van a jugar con su pareja. Jueguen por turnos a separar la torre y esconder una de las partes a sus espaldas” // “Now you will play with your partner. Take turns breaking the tower and hiding one part behind your back.”
• 10 minutes: partner work time
• Monitor for students who use a 10-frame or their fingers to figure out how many cubes are hiding.

• Invite previously identified students to share.
• “¿Cómo descifraron cuántos cubos estaban escondidos a las espaldas de su compañero?” // “How did you figure out how many cubes were hiding behind your partner’s back?”

The purpose of this activity is for students to choose activities focusing on adding and subtracting within 10. Students choose from three centers introduced in the previous section and one introduced in the previous activity.

• What’s Behind My Back
• Five in a Row: Addition and Subtraction
• Check it Off
• Find the Pair

Students may work with more than one center during this time. Keep the materials from each center organized to use in future lessons.

• Gather materials from previous centers:
  • What’s Behind My Back, Stage 2
  • Five in a Row: Addition and Subtraction, Stages 1 and 2
  • Check it Off, Stages 1 and 2
  • Find the Pair, Stage 2

• Groups of 2
• “Ahora van a escoger centros de los que ya conocemos” // “Now 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

• Invite students to work at the center of their choice.
• 8 minutes: center work time
• “Escojan qué les gustaría hacer ahora” // “Choose what you would like to do next.”
• 8 minutes: center work time

• “¿Cómo saben que el centro que escogieron fue una buena elección?” // “How do you know that the center you chose was a good choice?”