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Activity 1

Standards Alignment

Building On

Addressing

Instructional Routines

None

Materials

None

Activity Narrative

This activity develops students’ understanding of hours and minutes as units of time, and helps them to see 1 hour as 60 times as long as 1 minute.

In converting hours to minutes, students may reason additively when the time in hours is a low single-digit number, but likely will reason multiplicatively when converting, say, 8 or 10 hours into minutes. When they relate the operation of multiplication by 60 to converting hours to minutes, students make use of structure (MP7). To convert fractional numbers of hours (, and hour), students might choose to think in multiplicative terms (for instance, ) but are not expected to do so. Instead they can rely on their prior knowledge of “quarter of an hour” and “half an hour” to reason about the number of minutes.

MLR8 Discussion Supports. Synthesis: Some students may benefit from the opportunity to rehearse with a partner what they will say before they share with the whole class.
Advances: Speaking

Launch

Groups of 2
“On a weekday, how do you spend the hours between the time you wake up and the time you go to bed? How much time do you spend getting ready for school, going to school, and at school? How do you spend your time after school?”
“Take a quick minute to list your usual weekday routine, knowing that it may vary from day to day. You may choose to focus on only one day—say, Monday.”
1–2 minutes: quiet think time
1–2 minutes: partner discussion
“How did you show the amount of time you spend on each activity?” (In hours, in minutes, as intervals of time—for example: 8:30 to 3:30.)
“Let’s look at how Mai spends her day in hours and minutes.”

Activity

7–8 minutes: independent work time
2–3 minutes: partner discussion
Monitor for the ways students convert large numbers of hours and fractional hours into minutes.

The table shows how Mai spends the time she is awake on a school day.

activity	hours	minutes
morning routine	1
getting to school
time at school	8
getting home from school
homework and reading
playing and family time	2
bedtime routine

Complete the table to show how many minutes Mai spends on each activity.
How many hours does Mai spend at school? What is the time in minutes?
How many minutes does Mai sleep on a school night? Explain or show your reasoning.

Activity Synthesis

Invite selected students to share their responses and their reasoning. Start with students who reason additively about the number of minutes in a given number of hours. End with those who frame the relationship between a whole number of hours and the number of minutes in multiplicative terms.

Activity 2

Standards Alignment

Building On

Addressing

Instructional Routines

None

Materials

None

Activity Narrative

In this activity, students reason about the number of seconds given time in minutes. Students see that 1 minute is 60 times as long as 1 second.

Engagement: Internalize Self-Regulation. Synthesis: Provide students an opportunity to self-assess and reflect on their own progress. For example, say, “This is our sixth day working on problems about measurement and conversion. What have you learned about these topics? What topics do you still want to learn about?”
Supports accessibility for: Memory, Social-Emotional Functioning

Launch

Groups of 2
“Have you used a timer or a stopwatch to count the number of seconds of doing something? What were you timing?”
Consider challenging students to do something for a full minute (for instance, holding breath or balancing on one foot) and displaying a timer that shows the second hand or the number of seconds increasing or decreasing.
“Which one is longer: 1 minute or 1 second? How does 1 minute compare to 1 second?” (One minute is 60 times as long as 1 second.)

Activity

7–8 minutes: independent work time
2–3 minutes: partner discussion
Monitor for the different ways students find the number of seconds in 10 minutes and in 30 minutes, and the ways they reason about the last two problems.

Diego sets a timer to make sure his daily activities do not take too long or too short an amount of time.

activity	minutes	seconds
brushing teeth	2
showering	3
heating a cup of milk in the microwave
break during homework time	5
quick workout	10
daily reading	30

Complete the table, with the number of seconds for each activity.
Diego notices on a television channel that commercial breaks often are between minutes and minutes long. How long are they in seconds? Explain or show your reasoning.
Diego’s workout starts with 4 minutes of warming-up and stretching, followed by 100 seconds of jumping jacks.

If he works out for 10 minutes exactly, how many more seconds are left in his workout?

Student Response

to access Student Response.

Advancing Student Thinking

Activity Synthesis

Display the table. Invite students to help complete the table by sharing their responses and their reasoning.
“How did you find the number of seconds in 30 minutes?” (Multiply the number of seconds in 10 minutes by 3, multiply the number of seconds in 5 minutes by 6.)
Select other students to share their reasoning for the problem about commercial breaks.
Highlight that we can decompose the number of minutes to find the number of seconds. (For example, minutes is 1 minute and minute or 1 minute and 30 seconds, which is 90 seconds.)

Lesson Synthesis

“Today we used hours, minutes, and seconds to express lengths of time. We converted hours to minutes, and minutes to seconds.”

Display two tables as shown:

hours	minutes
1
5
10

minutes	seconds
1
5
10

“If someone claims that the missing numbers in the first table are the same as the missing numbers in the second table, would you agree? Why or why not?” (Agree. An hour is 60 minutes or 60 times as long as 1 minute, and a minute is 60 seconds or 60 times as long as 1 second. The relationship between hour and minutes is the same as that between minute and seconds.)

Complete the table as a class.

Consider asking, “How can we use the information in the tables to help us find the number of seconds in 1 hour?”

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Lesson 12

Hours, Minutes, and Seconds

Warm-up

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Student Response

Advancing Student Thinking

Activity Synthesis

Activity 1

Standards Alignment

Building On

Addressing

4.MD.A.1

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Activity Synthesis

Activity 2

Standards Alignment

Building On

Addressing

4.MD.A.1

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Student Response

Advancing Student Thinking

Activity Synthesis

Lesson Synthesis

Standards Alignment

Building On

Addressing

Building Toward

Student Response

Advancing Student Thinking

4.MD.A.2

4.OA.A.3

Building Toward

4.MD.A.2

4.OA.A.3

Building Toward