# Lesson 15

Escribamos horas

## Warm-up: Verdadero o falso: Cercano a 30 (10 minutes)

### Narrative

The purpose of this True or False is to elicit understandings students have for the meaning of the equal sign. Students may reason about whether the expressions on either side of the equal sign are the same without finding their values by using the properties of operations or their understanding of place value (MP7).

### Launch

• Display one statement.
• “Hagan una señal cuando sepan si la afirmación es verdadera o no, y puedan explicar cómo lo saben” //  “Give me a signal when you know whether the statement is true and can explain how you know.”
• 1 minute: quiet think time

### Activity

• Share and record answers and strategies.
• Repeat with each statement.

### Student Facing

En cada caso, decide si la afirmación es verdadera o falsa.

Prepárate para explicar tu razonamiento.

• $$30 = 30$$
• $$10 + 15 = 15 + 10$$
• $$10 + 10 + 10 = 3$$

### Activity Synthesis

• “¿Cómo pueden explicar su respuesta sin encontrar el valor de la suma a cada lado del signo igual?” // “How can you explain your answer without finding the value of the sum on both sides of the equal sign?”

## Activity 1: Contemos los minutos (10 minutes)

### Narrative

The purpose of this activity is to connect 30 minutes to telling the time at the half hour. Students learn that there are 30 minutes in half an hour by counting the intervals around an analog clock that represent the minutes. Some students may count by ones, but others may notice a pattern and count by 5 or 10 (MP7). Although some students may point out that 30 is half of 60, this relationship is beyond grade-level expectations.

### Launch

• Groups of 2
• Display the clock in the student book.
• “Cada una de las pequeñas líneas alrededor del reloj representa un minuto” // “Each of the little lines around the clock represents a minute.”

### Activity

• “Empiecen en la marca de arriba, en las 12, y cuenten la mitad del reloj. ¿Cuántos minutos hay?” // “Start at the top mark, at the 12, and count half of the clock. How many minutes is that?"
• “Marquen donde se detuvieron. Luego, hablen con su compañero para ver si están de acuerdo” // “Circle where you stop, then check with your partner to see if you agree.”
• 2 minutes: independent work time
• 1 minute: partner discussion
• Monitor for students to circle the mark below 6.

### Student Facing

Empieza en el 12.

Cuenta los minutos alrededor del reloj hasta que llegues a la mitad del reloj.

Marca donde te detuviste.

Síntesis:

### Activity Synthesis

• “¿Cómo llevaron la cuenta?” // “How did you keep track of your count?” (I counted by ones. I marked each time I got to ten, and did that 3 times.)
• Display clock showing 2:30.
• “¿Qué hora muestra este reloj?” // “What time does this clock show?” (Half past 2)
• “Acabamos de aprender que si contamos el número de minutos hasta la mitad del recorrido alrededor del reloj, hay 30 minutos. Cuando la manecilla de los minutos ha recorrido la mitad del reloj, es la hora y media. Podemos escribir la hora así: 2:30. El 2 representa la hora y el 30 representa los minutos” // “We just learned that if we count the number of minutes halfway around the clock, we count 30 minutes. When the minute hand has gone half way around the clock, the time is half past. We can write the time as 2:30. The 2 represents the hour and the 30 represent the minutes.”
• Display clock showing 4:30.
• “¿Cómo escribiríamos esta hora?” // “How would we write the time?” (4:30)

## Activity 2: Todo el tiempo del mundo (25 minutes)

### Narrative

The purpose of this activity is for students to write time to the hour and half hour based on clocks with one or both hands.
MLR8 Discussion Supports. Synthesis: For each observation that is shared, invite students to turn to a partner and restate what they heard using precise mathematical language.
Engagement: Develop Effort and Persistence. Chunk this task into more manageable parts. Check in with students to provide feedback and encouragement after each chunk.
Supports accessibility for: Attention, Social-Emotional Functioning

### Required Materials

Materials to Gather

### Required Preparation

• Each student needs their Half Past Clock Cards from a previous lesson.

### Launch

• Groups of 2
• Give students their Half Past Clock Cards.
• “Escriban las horas en las nuevas tarjetas de reloj que muestran la hora y media” // “Write the times on the new clock cards that show half past.”
• 2 minutes: independent work time

### Activity

• “¿Qué hora se muestra en cada reloj? Trabajen de manera independiente en las preguntas y luego comparen su trabajo con el de su compañero” // “What time is shown on each clock? Work on the questions by yourself and then compare your work with your partner’s.”
• 7 minutes: independent work time
• 3 minutes: partner discussion

### Student Facing

1. Escribe la hora en cada reloj.
1.

2.

3.

4.

2. En cada reloj, dibuja la manecilla de los minutos y escribe la hora.
1.

2.

3.

4.

5.

3. Este reloj solo tiene la manecilla de los minutos.
¿Qué hora podría ser?
Dibuja la manecilla de las horas y escribe la hora.

Si te queda tiempo: ¿Qué otras horas puedes mostrar en el reloj?

### Activity Synthesis

• Display the clock with the hour hand pointing between the 4 and the 5.
• “¿Cómo les puede ayudar la manecilla de las horas a saber si la manecilla de los minutos debe señalar el 12 o el 6?” // “How can the hour hand help you know if the minute hand should point to the 12 or the 6?” (If the hour hand points to a number, then the minute hand points to 12. If the hour hand points halfway between two hours then the minute hand points to the 6.)
• “¿Cómo supieron que había que escribir :30 en la hora escrita?” // “How did you know to put :30 in the written time?” (When the minute hand is on the 6, 30 minutes have gone by so it is _:00.)
• Display the problem where students draw in the hour hand and write the time.
• “¿Cómo supieron a dónde debía apuntar la manecilla de las horas?” // “How did you know where to put the hour hand?” (The hour hand has to point between 2 numbers because it is ‘half past’.)

## Lesson Synthesis

### Lesson Synthesis

Display a clock showing 3:30 and a clock where the hands are reversed (the hour hand points to 6 and the minute hand points to 3):

“Hoy vimos relojes que mostraban horas en punto y también horas y media. ¿Cuál reloj muestra las 3:30? ¿Cómo lo saben?” // “Today we saw clocks showing time to the hour and half past the hour. Which clock shows 3:30? How do you know?” (The second clock. The small hour hand points halfway between the 3 and the 4.)