Lesson 9

The purpose of this Estimation Exploration is for students to make sense of times that would be reasonable with only the hour hand as a reference on a clock. 

• Groups of 2
• Display image.
• “¿Qué estimación sería muy tarde?, ¿muy temprano?, ¿razonable?” // “What is an estimate that’s too late?” “Too early?” “About right?”
• 1 minute: quiet think time

• “Discutan con su compañero cómo pensaron” // “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Record responses.

• “¿Cómo supieron que la hora era la 1?” // “How did you know that the hour was 1?” (The hour hand passes between 1 and 2 as the time goes from 1:00 to 2:00.)
• Consider asking:
  • “¿Cómo decidieron cuánto tiempo había pasado desde la 1:00?” // “How did you decide how far past 1:00 it was?” (It has to be a little past 1:30 since the hour hand is a little more than halfway between the 1 and the 2.)

The purpose of this activity is for students to tell and write time to the nearest minute. They learn that there are 60 small tick marks around the clock to show each of the 60 minutes in 1 hour. The work here gives students a reason to attend to the features of the clock and use them to tell time more precisely (MP6). The synthesis provides an opportunity to discuss how the clock does not indicate whether the time is a.m. or p.m.

• Groups of 2
• “Tómense un momento para pensar en la hora que Lin y Diego creen que muestra este reloj” // “Take some time to think about the time Lin and Diego think this clock is showing.”
• 1-2 minutes: quiet think time
• “Hablen con su compañero sobre con quién están de acuerdo y por qué” // “Talk to your partner about who you agree with and why.”
• 2 minutes: partner discussion
• Monitor for students who notice that the minute hand is not pointing to the 7 or the 8 but is in between the two numbers.
• Invite students to share their responses and reasoning.
• “Hay 60 marcas pequeñas alrededor del reloj para mostrar cada uno de los 60 minutos de 1 hora. Sabemos que es la 1:37 porque la manecilla de los minutos está en la marca número 37” // “There are 60 small tick marks around the clock to show each of the 60 minutes in 1 hour. We know it is 1:37 since the minute hand is at the thirty-seventh tick mark.”

• “Con su compañero, decidan qué hora muestra cada uno de estos relojes” // “Work with your partner to determine what time is shown on each of these clocks.”
• 2-3 minutes: partner work time
• Monitor for different ways that students determine the minutes, such as:
  • Counting by 5 and then by 1
  • Starting at a time they know and counting on or back

If students tell the time to the nearest 5 minutes, consider asking:

• “Cuéntame cómo encontraste la hora” // “Tell me how you found the time.”
• “¿Cómo puedes usar una hora que conoces para encontrar la hora al minuto más cercano?” // “How could you use a time that you know to find the time to the nearest minute?”

• Invite students to share how they knew the time on each clock. Emphasize strategies for telling time to the nearest minute.
• Consider asking:
  • “¿Hubo algunas horas que al principio los confundieron o que fueron más difíciles de leer?” // “Were there any times that confused you at first or were harder to tell?” (On the fourth clock, I thought the hour might be 8.)
  • “¿Alguien tiene sugerencias sobre cómo leer algunas de las horas que pueden crear confusión?” // “Does anyone have suggestions for how to handle some of the times that could create confusion?”
• If not mentioned by students, ask: “¿Pudieron saber si la hora en el reloj era a.m. o p.m.?” // “Were you able to tell whether the time on the clock was a.m. or p.m.?” (No, the clock doesn’t tell us whether it is a.m. or p.m., we’d need more information to know that.)

The purpose of this activity is for students to tell and write time to the nearest minute as they draw times on blank clocks.

• Groups of 2
• “Usemos lo que saben sobre cómo leer la hora al minuto más cercano para practicar la escritura de la hora en relojes” // “Let's use what you know about telling time to the nearest minute to practice writing times on clocks.”
• “¿Qué cosas importantes deben recordar cuando dibujan la hora en un reloj sin manecillas?” // “What are some important things to remember when you are drawing the time on a blank clock?” (Show the difference between the minute and hour hand clearly. Be careful in drawing the location of each hand.)
• 30 seconds: partner discussion
• Share responses.

• “Mientras trabajan, discutan con su compañero lo que van haciendo y las preguntas que tengan” // “As you work, discuss your work and any questions you have with your partner.”
• 5-7 minutes: partner work time

If students do not draw hands that are clearly different lengths for the hour hand and minute hand, consider asking:

• “Cuéntame cómo decidiste en dónde dibujar cada manecilla” // “Tell me about how you decided where to draw each hand.”
• “¿Qué puedes hacer para que sea más fácil diferenciar la manecilla de las horas de la manecilla de los minutos?” // “How could you make it easier to tell the hour hand from the minute hand?”

• Invite students to share the times they drew on the clocks. Emphasize how they distinguish between the hour and minute hands for someone else to be clear on the time they are showing.
• Consider asking:
  • “¿Hubo algunas horas que al principio los confundieron o que fueron más difíciles de mostrar?” // “Were there any times that confused you at first or were harder to show?” (For 3:18 I had to draw the hands really close together.)
  • “¿Alguien tiene sugerencias sobre qué hacer con algunas de las horas que pueden ser difíciles de mostrar?” // “Does anyone have suggestions for how to handle some of the times that might be hard to show?”
• “Cuando le dibujaron una hora a su compañero, ¿qué tuvieron que tener en mente?” // “When you were drawing a time for your partner, what did you have to keep in mind?” (To make sure to show the difference between the minute and hour hands clearly, to be precise in what minute the hand was pointing to.)