# Lesson 1

Sumas que sabemos

## Warm-up: Observa y pregúntate: Tabla de sumas (10 minutes)

### Narrative

The purpose of this warm-up is to elicit the idea that there are many sums within 10, and students may already know many of these sums. This will be useful when students identify sums they know and don’t know in a later activity.

### Launch

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

### Activity

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

### Student Facing

¿Qué observas?
¿Qué te preguntas?

### Activity Synthesis

• “Esta tabla muestra todas las sumas que se deben saber al finalizar el año. Como se dieron cuenta, ya se saben algunas” // “This table shows all the sums that you need to know by the end of the year. As you noticed, there are some you already know.”
• “Díganle a su pareja tres sumas que se sepan” // “Tell your partner three sums you know.”

## Activity 1: Mi suma favorita (15 minutes)

### Narrative

The purpose of this activity is for students to explore sums within 10. Students pick their favorite sum as an entry point to the next activity in which students sort the sums into those they know and those they don’t yet know. In this activity, students may choose any sum within 10 that they like.

MLR8 Discussion Supports. During group work, invite students to take turns sharing their responses. Ask students to restate what they heard using precise mathematical language and their own words. Display the sentence frame: “Te escuché decir . . .” //  “I heard you say . . .” Original speakers can agree or clarify for their partner.

### Launch

• Groups of 4
• Display the addition chart from the warm-up.
• “Van a escoger su suma favorita de la tabla de sumas. Por ejemplo, mi suma favorita es $$8 + 2 = 10$$ porque me gustan las sumas de 10” // “You are going to choose your favorite sum from the addition chart. For example, my favorite sum is $$8 + 2 = 10$$ because I like sums of 10.”

### Activity

• “Escojan una o dos sumas que sean sus favoritas. Expliquen por qué son sus favoritas. Usen dibujos, números o palabras” // “Pick one or two sums that are your favorite. Explain why they are your favorite using drawings, numbers, or words.”
• 4 minutes: independent work time
• “Compartan sus sumas favoritas con los demás estudiantes de su grupo” // “Share your favorite sums with the other students in your small group.”
• 4 minutes: small-group discussion
• Monitor for students who wrote equations with addends of 0 or 1, equations with the same addend twice, or sums of 10.

### Student Facing

Escoge tu suma favorita.

Escribe la ecuación: ________________________________

Muestra por qué es tu suma favorita. Usa dibujos, números o palabras.

### Activity Synthesis

• Invite previously identified students to share their favorite sums.
• “¿Por qué esta suma es de tus favoritas?" “Why is this sum a favorite of yours?”

## Activity 2: Sumas que ya me sé (25 minutes)

### Narrative

The purpose of this activity is for students to identify which sums within 10 they know and which they don’t know yet. Sums that students know from memory or that they have a quick mental method for should be categorized as “got it.” Consider giving each student two bags or envelopes to keep their cards separated for ease of practice. Label one bag “Got It” and the other “Not Yet.” As students know more sums from memory, they can move them to the “Got It” bag.

This activity provides an opportunity for formative assessment on students’ fluency with addition within 10. Use discretion in asking students to explain their answer, as some students will simply know the sums—or count on so quickly in their head that they may not be able to explain how they got it. These students should not be required to draw a picture to represent the sum.

Look for students who know sums such as $$3 + 4$$, $$3 + 5$$, $$6 + 3$$, and $$4 + 5$$, as these tend to be the most challenging for students and will be discussed during the lesson synthesis. After the lesson synthesis, collect the student workbook page to formatively assess sums students did not know.

Students use the addition expression cards in a future lesson.

Engagement: Develop Effort and Persistence. Support metacognition and motivation by drawing attention to the end-of-year fluency goal. “Al finalizar el año nos vamos a saber muchas sumas y diferencias hasta 10. Veamos cuáles sumas hasta 10 nos sabemos hoy para que sepamos cuáles podemos seguir practicando” // “By the end of this year, we will know many sums and differences within 10. Let’s see which sums within 10 we know today, so we know which ones we can keep practicing.”
Supports accessibility for: Social-Emotional Functioning, Attention

### Required Materials

Materials to Gather

Materials to Copy

• Compare Stage 1 Addition Cards to 10

### Launch

• Groups of 2
• Give each student scissors and a set of cards.
• “Primero, recorten sus tarjetas y mézclenlas” // “First, cut out your cards and mix them up.”
• 5 minutes: independent work time
• “Vimos que ustedes ya se saben el valor de muchas sumas. Ensayemos algunas juntos. Levanten su pulgar cuando sepan el valor de la suma” // “We saw that there are a lot of sums that you already know the value of. Let’s try some together. Give me a thumbs up when you know the value of the sum.”
• Display $$4 + 1$$.
• “¿Cómo saben esta suma?” // “How do you know this one?” (Adding 1 is quick. It’s just 1 more than the number.)
• “Esta es una suma que muchos de nosotros sabemos inmediatamente. Si ustedes saben rápidamente el valor de una suma, la van a poner en el montón de ‘ya me la sé’” // “This is a sum that many of us know right away. Any sum that you know the value of quickly is placed in the ‘got it’ pile.”
• Display  $$5 + 3$$.
• “Para esta suma, es posible que deba contar con mis dedos desde 5. Esta es una suma que puedo descifrar, pero tardo un poco más de tiempo. Cuando les tome un poco más de tiempo encontrar el valor de la suma, pongan esta tarjeta en el montón de ‘todavía no’” // “For this sum, I might have to count on my fingers from 5. This is a sum that I can figure out, but it takes just a bit longer. When it takes you a little longer to find the value of the sum, place that card in the ‘not yet’ pile.”

### Activity

• “Pongan primero sus tarjetas boca abajo, en un montón. Volteen una tarjeta a la vez y decidan a qué montón pertenece” // “Start with your cards in a pile, face down. Flip one card at a time and decide which pile it belongs in.”
• 10 minutes: independent work time
• “Anoten las sumas que todavía no se saben” // “Record the sums that you are still working on.”
• 3 minutes: independent work time
• Monitor for sums that many students have sorted under “not yet” for the the lesson synthesis.

### Student Facing

1. Pon tus tarjetas boca abajo, en un montón.
2. Voltea la tarjeta y di la expresión.
3. Si puedes decir el valor de la suma inmediatamente, ponla debajo de “ya me la sé”.
4. Si te toma un tiempo encontrar el valor, ponla debajo de “todavía no”.
ya me la sé todavía no

### Activity Synthesis

• “¿Qué patrones ven en las sumas que se saben? ¿Por qué?” // “What patterns do you see in the sums you know? Why?” (I know all the +1 sums. I know all the sums of 10.)
• “¿Qué sumas son más difíciles de encontrar?” // “Which sums are more difficult to find?” (The sums that have two bigger numbers, like 4 + 5, are harder.)
• “Al finalizar el año, van a saber rápidamente cuál es la suma de todas las expresiones de suma hasta 10” // “By the end of the year, you are going to be able to quickly tell the sum for all the addition expressions within 10.”

## Lesson Synthesis

### Lesson Synthesis

Display three common “not yet” expressions. Consider showing expressions such as $$3 + 5$$, $$4 + 5$$, and $$6 + 3$$.

“Hoy buscamos sumas que ya nos sabemos para decidir qué sumas seguir practicando. Algunos estudiantes se saben la suma $$3 + 5 = 8$$. ¿Qué método pueden usar para ayudarle a un amigo que no se sabe todavía el valor de esta suma?” // “Today we looked for sums we know, so we know which sums to continue practicing. Some students know $$3 + 5 = 8$$. What is a method you can use to help a friend who doesn’t know the value of this sum yet?” ($$3 + 5$$ is the same as $$5 + 3$$. They can count on 3 quickly. 5...6, 7, 8.)

Highlight and record 2–3 student methods for more challenging sums. These methods can be displayed in the classroom for students to refer to later in this section and unit.