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Launch

Groups of 2
Display the image.
“What is an estimate that’s too high? Too low? About right?”
1 minute: quiet think time

Activity

“Discuss your thinking with your partner.”
1 minute: partner discussion
Record responses.
“Which groups on the field did you count as part of the marching band?” (I counted only the performers in the band uniforms. I included everyone on the field.)

Student Task Statement

How many people are in the marching band?

Record an estimate
that is:

too low	about right	too high

Student Response

to access Student Response.

Advancing Student Thinking

Are You Ready for More?

Activity 1

10 mins

About 100? Close to 100?

Standards Alignment

Building On

Addressing

Building Toward

Instructional Routines

None

Materials

None

Activity Narrative

The purpose of this activity is for students to think about what it means for numbers to be close to multiples of 100. There is no definition given about what “close to” means during the activity, so students may interpret the term in different ways.

Action and Expression: Develop Expression and Communication. Synthesis: Identify connections between strategies that result in the same outcomes but use different approaches.
Supports accessibility for: Memory

Launch

Groups of 2
Display the first problem.
“Take a minute to look at the numbers of people in different parts of a school during a school day. What do you notice? What do you wonder?” (There are about the same number of people in the library and the music room. There are a lot of people in the school. Are there any other places where people could be in the school?)
1 minute: quiet think time
Share and record responses.

Activity

“For each room, decide if there are about 100 people in the room or not. Record the numbers in the table. Be prepared to explain how you decide if a number is or is not about 100.”
2 minutes: independent work time
Share responses.
“Now work with your partner to decide if the number of people in each part of the school is close to 0, close to 100, or close to 200. If you don’t think a number belongs in any column, set it aside. Be prepared to explain your reasoning.”
2–3 minutes: partner work time
Monitor for students who provide reasoning for where they would place 36, 49, 52, and 163. Ask them to share during the Activity Synthesis.

Student Task Statement

Here are the numbers of people in different parts of a school at noon during a school day.
- playground: 94
- cafeteria: 163
- art room: 36
- library: 49
- classrooms: 216
- gymnasium: 109
- music room: 52
Where in the school would you say that there are about 100 people?

Record the numbers in the table. Be prepared to explain your reasoning.

about 100 not about 100
Now decide if the number of people in each part of the school is close to 0, close to 100, or close to 200.

If you don’t think a number belongs in any column, set it aside. Be prepared to explain your reasoning.

close to 0 close to 100 close to 200

Student Response

to access Student Response.

Advancing Student Thinking

Are You Ready for More?

Activity Synthesis

“How did you decide whether a number is close to 0, 100, or 200?” (I thought about whether it was almost that number, like 94 is almost 100. I decided between the choices that were there—like for 163, it was closer to 200 than to 0 or 100.)
“How did you decide if a number doesn’t belong to any of these groups?” (If a number seemed far away from all the choices, then I set it aside. Like 52 wasn’t close to 0 or 100 because it’s almost right in the middle.)
“What if the table showed ‘closer to 0,’ ‘closer to 100,’ and ‘closer to 200?’ Would it change where each number goes? Would you be able to place all the numbers in the table?” (Yes, because I would just be choosing the number that’s closer than the other numbers, not saying it’s really close to the number.)

Activity 2

25 mins

Close to Multiples of 100

Standards Alignment

Building On

Addressing

Building Toward

Instructional Routines

None

Materials

None

Activity Narrative

The purpose of this activity is for students to locate two- and three-digit numbers on a series of number lines. The endpoints of each number line are multiples of 100, and the space between them is partitioned into ten equal intervals. As they locate the numbers, students recognize each tick mark as a multiple of 10. Later in the activity, students use a number line to name the closest multiple of 100 to a given number. When students choose the correct number line and accurately place each number on the number line, they attend to precision and show an understanding of place value (MP6, MP7).

MLR8 Discussion Supports: Create a display of the number lines. As students share their strategies, annotate the display to illustrate connections. For example, as students talk about their numbers and number lines, write each number below the appropriate tick mark, and draw an arrow to show the closest multiple of 100 they identified.
Advances: Speaking, Representing

Launch

Groups of 4
“What do you know about the number line?” (Each point on the number line can represent a number. I can add or subtract by moving right or left on the number line. It can show the distance between numbers, like the number 10 is 10 away from 0.)
1 minute: quiet think time
Share and record responses.
“Take a look at the number lines in the first problem. What do you notice about them? What do you wonder?” (Students may notice: Each number line has two multiples of 100. There are tick marks between the numbers. Students may wonder: Why don’t the number lines go higher or lower? What numbers do the tick marks represent?)
30 seconds: quiet think time
Share responses.
Display the number line:
“Do you see multiples of 100 in this number line?” (Yes, 100 and 200)
“What numbers do you think the unlabeled tick marks represent?” (Tens, groups of 10, numbers that we get if we count up by 10 starting from 100, multiples of 10) “Let’s name them!” (100, 110, . . . , 200)
Label the first few tick marks.
“Can you estimate where 113 goes on the number line?” (Between the second and third tick marks, but closer to the second tick mark. Or between 110 and 120, but closer to 110.)
Assign 1 set of numbers (A, B, C, D, or E) to each group of 4 students.

Activity

“Work with your group to decide on which number line each number should go. Locate each number on the number line with a dot, and label it. Then complete the second problem.”
5–7 minutes: small-group work time
After students place 364 on a number line, pause for a discussion. Ask each group to share one of their numbers and how they knew on which number line to place it.
“On which number line did you place 364?” (The number line with 300 and 400.)
“How did you decide which multiple of 100 was closer?” (Once I located 364 on my number line, I could tell it was closer to 400. I counted the tick marks back to 300 and on to 400. There were fewer tick marks to get to 400, so it was closer.)
“Complete the last problem on your own.”
2–3 minutes: independent work time

Activity Synthesis

“How can you tell which multiple of 100 is closer to a number?” (The endpoints of the number lines are multiples of 100. From the number line, we can tell whether a point is closer to one end or the other. We can tell if a point is in the lower half or the upper half of the number line. We can count the tick marks to each multiple of 100 to decide which is closer.)
As needed, “Was 0 the nearest multiple of 100 for any of the numbers? How do you know?” (Yes. From the number line, we could see that some numbers, like 11, were closer to 0 than to 100. So, we said 0 was the nearest multiple of 100.)

Your teacher will assign a set of numbers to you.

A	94	36	109	163	229
B	24	52	216	11	481
C	187	135	67	83	241
D	332	154	408	296	45
E	279	205	377	449	73

Work with your group to decide on which number line each number should go. Then locate and label each number on the number line.
Locate and label 364 on the correct number line.
1. Name the 2 multiples of 100 that are closest to 364.
2. Of the 2 multiples of 100 you named, which is closer to 364?
Write the numbers assigned to you earlier. For each number, name the nearest multiple of 100.

number

nearest multiple of 100

A	94	36	109	163	229
B	24	52	216	11	481
C	187	135	67	83	241
D	332	154	408	296	45
E	279	205	377	449	73

A	94	36	109	163	229
B	24	52	216	11	481
C	187	135	67	83	241
D	332	154	408	296	45
E	279	205	377	449	73

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Lesson 13

Multiples of 100

Warm-up

Estimation Exploration: Marching Band

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Student Task Statement

Student Response

Advancing Student Thinking

Are You Ready for More?

Activity Synthesis

Activity 1

About 100? Close to 100?

Standards Alignment

3.NBT.1

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Student Task Statement

Student Response

Advancing Student Thinking

Are You Ready for More?

Activity Synthesis

Activity 2

Close to Multiples of 100

Standards Alignment

3.NBT.1

Instructional Routines

Materials

Activity Narrative

Launch

Activity

Activity Synthesis

Lesson Synthesis

Have feedback on the curriculum?

Standards Alignment

3.NBT.1

Student Task Statement

Student Response

Advancing Student Thinking

Are You Ready for More?

A	94	36	109	163	229
B	24	52	216	11	481
C	187	135	67	83	241
D	332	154	408	296	45
E	279	205	377	449	73