Lesson 14

The purpose of this Number Talk is to elicit strategies and understandings students have for adding within 100.

• Display one expression.
• “Hagan una señal cuando tengan una respuesta y puedan explicar cómo la obtuvieron” // “Give me a signal when you have an answer and can explain how you got it.”
• 1 minute: quiet think time

• Record answers and strategies.
• Keep expressions and work displayed.
• Repeat with each expression.

• “¿Alguien puede expresar el razonamiento de _______ de otra forma?” // “Who can restate _______ 's reasoning in a different way?”
• “¿Alguien usó la misma estrategia, pero la explicaría de otra forma?” // “Did anyone have the same strategy but would explain it differently?”

The purpose of this activity is for students to see that the hour hand doesn’t always point directly at a number on the clock. Students see that the hour hand can be between two hours. The end of the activity synthesis provides an opportunity for formative assessment of students’ understanding of the language of “half past” which they will continue developing in the next activities.

• Each student needs their clock cards from the previous lesson.

• Groups of 2
• Give each student their clock cards from the previous lesson, a copy of the blackline master, and scissors.
• Display the image from the student book.
• “¿Qué observan? ¿Qué se preguntan?” // “What do you notice? What do you wonder?”
• 1 minute: quiet think time
• 1 minute: partner discussion
• Share and record responses.

• “Recorten las nuevas tarjetas y pónganlas junto a sus otras tarjetas de reloj. Luego, organicen todas las tarjetas de una manera que tenga sentido para ustedes. Prepárense para explicar cómo organizaron las tarjetas” // “Cut out your new cards and put them with your other clock cards. Then organize all the cards in a way that makes sense to you. Be ready to explain how you organized the cards.”
• 5 minutes: independent work time

• Display cards showing 7:00, 7:30, 8:00
• “_______ ordenó sus relojes así. ¿Por qué creen que lo hizo así?” // “_______ put their clocks in this order. Why do you think they did that?” (The hour hand is moving from the 7 to the 8 and on the middle clock, it’s in between.)
• “En el segundo reloj, la manecilla de las horas está en el medio entre el 7 y el 8, así que podemos llamar a esa hora las ‘7 y media’” // “On the second clock, the hour hand is halfway between the 7 and the 8, so we can name the time as ‘half past 7.’”
• “Levanten la tarjeta que muestra las 3 y media. Levanten la tarjeta que muestra las 12 y media” // “Hold up the card that shows half past 3. Hold up the card that shows half past 12.”

The purpose of this activity is for students to identify whether a clock is showing a time that’s half past or o’clock. Students use the position of the hour hand to determine the time.

• Each student needs red and blue colored pencils, crayons, or markers.

• Groups of 2
• Give each student a red and a blue colored pencil, crayon, or marker.
• Display clock cards for 9:00 and half past 9.
• “¿Cuál tarjeta muestra las 9 en punto y cuál tarjeta muestra las 9 y media?” // “Which card shows 9 o’clock and which card shows half past 9?”
• 1 minute: partner discussion
• Share responses.

• Read the task statement.
• 5 minutes: partner work time

Students may say that a time is half past the greater number of the two numbers the hour hand is between because the arrow is pointing at a position lower (or past) the greater number when looking at the numbers from top to bottom. Ask students to explain their method for telling the time. Consider asking:

• “¿Puedes mostrarme cómo se mueve la manecilla alrededor del reloj? Empieza en el 12” // “Can you show me how the arrow hand moves around the clock? Start at the 12.”
• “¿Cuál es el primer número que dices al contar del 1 al 12? ¿Por cuál número pasa primero la manecilla de las horas al recorrer el reloj?” // “Which number do you say first when you count from 1 to 12? Which number does the hour hand pass by first on its way around the clock?”

• Display clock showing half past 2.
• “Mai dice que son las 2 y media, pero Tyler dice que son las 3 y media. ¿Con quién están de acuerdo? ¿Por qué están de acuerdo con lo que dice?” // “Mai says it’s half past 2, and Tyler says it’s half past 3. Who do you agree with? Why do you agree with them?” (I agree with Mai because when you start at the top of the clock and go around, you start at 1, then 2. The hour hand is putting past 2. It looks like its pointing in between 2 and 3).

The purpose of this activity is for students to connect their understanding of half of a circle to the minute hand moving halfway around the face of a clock (MP7). Students watch a display clock to see that as the minute hand goes around the clock, the hour hand goes from one hour to the next. In the activity synthesis, students add the minute hand to their half-past clock cards. In the next lesson, students will connect half past to 30 minutes to write times in hours and half hours.

Use a display clock set to 10:00 and show the minute hand moving around until the clock shows 11:00. If a display clock is not available, this video can be used.

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

• Groups of 2
• Display the clocks in the student book.
• “¿Qué observan acerca de estos relojes?” // “What do you notice about these clocks?” (One shows 4 o’clock and the other shows half past 4. One is shaded. Half of the clock is shaded.)
• “Ahora vamos a ver las manecillas del reloj moverse a medida que el tiempo pasa” // “Now we will watch the hands on the clock move as time goes by.”

• Display demonstration clock or video.
• “¿Qué observan? ¿Qué se preguntan?” // “What do you notice? What do you wonder?”
• 1 minute: quiet think time
• 1 minute: partner discussion
• Share and record responses.

• “Cuando la manecilla de los minutos le da toda la vuelta al círculo, ha pasado una hora completa. La manecilla de las horas se mueve de una hora a la siguiente. Cuando la manecilla de los minutos da media vuelta en el reloj, la manecilla de las horas se mueve a la mitad entre una hora y la siguiente” // “When the minute hand moves all the way around the circle, a whole hour has passed. The hour hand moves from one hour to the next. When the minute hand moves halfway around the clock, the hour hand moves halfway from one hour to the next.”
• “Pongamos la manecilla de los minutos en nuestras nuevas tarjetas de reloj para la hora y media” // “Let’s put the minute hand on our new half past clock cards.”