Grade 1 Module 5 Lesson 3 by Great Minds

LESSON 3

Recognize the place value of digits in a two-digit number. Lesson at a Glance

Name

Circle all the groups of 10.

Students work with sets of objects to compose as many groups of 10 as they can. They record their work by writing the total in both standard form and as the number of tens and ones. The terms compose, value, and place (as in place value) are introduced in this lesson.

Key Question

tens

Total

ones

• What is the value of each digit in a two-digit number? How do you know?

Achievement Descriptors

1.Mod5.AD1 Represent a set of up to 99 objects with a two-digit

number by composing tens. (1.NBT.A.1, 1.NBT.B.2.a) 1.Mod5.AD3 Determine the values represented by the digits of a

two-digit number. (1.NBT.B.2)

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EUREKA MATH2

Agenda

Materials

Lesson Preparation

Fluency

Teacher

The Tens and Ones removables must be torn out of student books and placed in personal whiteboards. Consider whether to prepare these materials in advance or to have students prepare them during the lesson.

Launch Learn

10 min 5 min

35 min

• 100-bead rekenrek • Hide Zero® cards, demonstration set

• Place Value

Students

• Tens and Ones

• Tens and Ones removable (in the student book)

• Compose Tens • Problem Set

Land

• Hide Zero® cards (1 set per student pair)

10 min

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Fluency

EUREKA MATH2

Whiteboard Exchange: 5 as an Addend Students find a total and use the commutative property to write a related addition sentence to build addition fluency within 20. After each prompt for a written response, give students time to work. When most students are ready, signal for them to show their whiteboards. Provide immediate and specific feedback. If students need to revise, briefly return to validate their corrections. Display 1 + 5 =

1+5= 6

Write the equation, and then find the total. Display the completed addition sentence: 1 + 5 = 6.

5+1= 6

Change the order of the addends to write a related addition sentence. (Point to the addends.) Display the related addition sentence: 5 + 1 = 6. Repeat the process with the following sequence:

2+5

4+5

8+5

5+5

0+5

9+5

6+5

3+5

7+5

5-Groups: 20 and Some More Students recognize a group of dots and say the number two ways to prepare for identifying a given set with all the tens composed. Display the 5-group cards that show 20. How many dots? Raise your hand when you know. Wait until most students raise their hands, and then signal for students to respond. 20 44

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EUREKA MATH2

We can say 20 is 2 tens. On my signal, say it with me. Ready? 20 is 2 tens. Repeat the process with the following sequence: 21 2 tens 1 one

25 2 tens 5 ones

29 2 tens 9 ones

30 3 tens

34 3 tens 4 ones

36 3 tens 6 ones

40 4 tens

43 4 tens 3 ones

As students are ready, challenge them to recognize the groups of dots more quickly by showing each 5-group set for a shorter time.

Counting on the Rekenrek by Tens and Ones Materials—T: 100-bead rekenrek

Students count to a specified number the Say Ten way, then in standard form to prepare for identifying a given set with all the tens composed. Show students the rekenrek. Start with all the beads to the right side. Let’s count to 52 the Say Ten way. Say how many beads there are as I slide them over. Slide over 10 beads in each row all at once as students count to 5 ten. 1 ten, 2 ten, 3 ten, 4 ten, 5 ten Student View Copyright © Great Minds PBC

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EUREKA MATH2

Slide over 2 more beads, one at a time, as students count to 5 ten 2. 5 ten 1, 5 ten 2 Slide all the beads back to the right side. Let’s count to 52 the regular way. Say how many beads there are as I slide them over. Repeat the process as students count by tens and ones to 52. 10, 20, 30, 40, 50, 51, 52 Repeat the process as students count by tens and ones the Say Ten way and in standard form to the following numbers:

5 ten 7 57

7 ten 4 74

7 ten 9 79 Teacher Note

Launch

Students see a group of items composed into tens and ones and discuss how they are composed. Have students watch part 1 of the video, which shows a baker boxing doughnuts as they come down a conveyor belt. Invite students to discuss what they notice and wonder. I noticed he made a box of 10 donuts. Are there 50 donuts in all? I wonder if he will make more boxes of 10.

To fully grasp place value concepts, students need experience with groupable pictorial models. Although items in pictorial models cannot be physically grouped, students can still compose units. They may circle 10 items or group them in other ways to show that 10 items go together to make 1 ten. They may also rename the group by saying 1 box of doughnuts rather than 10 doughnuts, for example. They are internalizing that 10 ones are equivalent to 1 ten. Many pictorial models are proportional: The next unit is visually ten times larger than the base unit from which it is composed.

EUREKA MATH2

Play part 2, which shows the baker making progress toward boxing all the doughnuts. The baker is making full boxes. Can he fill more boxes with the doughnuts that are left? How do you know? He can make more. He puts 10 doughnuts in a box. There are more than 10 doughnuts left. Play part 3, which shows 5 complete boxes and 3 leftover doughnuts. Why do you think the baker did not put the last 3 doughnuts in a box? Because he’s making full boxes of 10 doughnuts, and 3 doughnuts won’t fill a box.

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Language Support

Support understanding of the term compose by having students make ten. Ask them to lace their fingers together and say, “I composed a ten by putting together 10 ones.” Show other examples of composition, such as these: • A table group is composed of 4 desks.

The baker composed as many boxes of 10 doughnuts as he could. To compose means to put together or group. Many of us compose groups of 10 when we count a collection.

• Our class is composed of 24 students.

What did the baker compose?

• A painting can be composed of many shapes and colors.

Groups of 10 doughnuts

• A band is composed of many musical instruments.

Transition to the next segment by framing the work. Today, we will find the total number of doughnuts. We will talk about how many tens and ones are in the total.

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Learn

EUREKA MATH2

Place Value Materials—T: Hide Zero cards

Students analyze a two-digit number and see that it is made of tens and ones. Teacher Note Display the image of the baker’s doughnuts as he first begins to box them. First the baker composed 1 box of 10 doughnuts. He had 43 more doughnuts, or ones, to box.

Unit form is a way of representing numbers in terms of place value units. For example, 48 can be written as 4 tens 8 ones or 3 tens 18 ones. Unit form is helpful for these reasons:

Record this as 1 ten 43 ones. Display the image of the doughnuts at the end of the video. The baker composed as many tens as he could. How many boxes, or tens, did he compose? 5 tens How many extra doughnuts, or ones, did he have left? 3 ones Record this as 5 tens 3 ones. Invite students to think–pair–share about the total number of doughnuts in the video. What is the total number of doughnuts? 53

• The unit is written to the right of the number so that students read left to right. • Units may be presented in a different order. For example, 43 can be written as 3 ones 4 tens. • When ones or tens are not fully grouped (e.g., 2 tens 43 ones), it may be easier for students to identify totals when they are written in unit form rather than shown on a place value chart. On a place value chart, students are more likely to mistake 2 in the tens and 43 in the ones as the number 243. Unit form is familiar from previous modules. However, students do not need to know it by name. The place value chart is introduced in lesson 6.

Support students as needed by chorally counting doughnuts by tens and ones. Show 53 using Hide Zero cards.

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EUREKA MATH2

Numbers with two digits have two places. This is the tens place. (Point to 5.) And this is the ones place. (Point to 3.) Tell students that the digit in the tens place tells how many tens are in the number. The digit in the ones place tells how many ones are in the number.

Language Support

Consider making a chart to help students remember new terms.

What are the places in a number with two digits? The tens place and the ones place In 53, what digit is in the tens place? 5

5 03

(Point to the image of the doughnuts.) How many is 5 tens? 50

50 3

When 5 is in the tens place, it has a value of 50. Value tells how much something is worth. What digit is in the ones place? 3 3 is in the ones place. What is the value of 3 ones? 3 Display the picture of Hide Zero cards for 53 that are separated. 53 is made of 50 and 3. (Draw arms to form a number bond.) That is 5 tens and 3 ones. (Point to the digits in 53.)

5 03

50 3

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EUREKA MATH2

Tens and Ones Materials—S: Tens and Ones removable, Hide Zero cards

Students find the value of digits in the tens and ones places and reason about their relationship to the total. Make sure students have inserted a Tens and Ones removable into their whiteboard. Display the picture of 35 doughnuts. The baker made this many doughnuts the next day. Invite students to think–pair–share about the number of tens shown in the picture. How many tens did he compose? How many ones are left? He composed 3 tens. There are 5 ones left. Have students record the number of tens and ones.

What is the total number of doughnuts? 35 Tell students to record the total in the number bond.

30 3

What are the digits in 35?

tens

5 5

ones

3 and 5 What place is 3 in? The tens place EM2_0105TE_A_L03_removable_tens_and_ones_studentwork1_CE.indd 15

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What is the value of 3 in 35? How do you know? 30 There are 3 tens. 10, 20, 30. Tell students to record the value of the digit 3 in the number bond as shown.

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EUREKA MATH2

What place is 5 in?

3 05

The ones place What is the value of 5 in 35? How do you know? 5

3 0

There are 5 ones. 1, 2, 3, 4, 5. Tell students to record the value of the digit 5 in the number bond as shown.

Support students as needed by having them use Hide Zero cards to show the total. They can separate them to show the value of the digits.

Teacher Note

Compose Tens Materials—S: Tens and Ones removable

Name

Circle all of the groups of 10.

Students compose groups of 10 within a set of objects and represent the total in terms of tens and ones.

Consider having students play Spill and Snap to provide additional practice with composing tens. Students take two big handfuls of cubes and spill them onto a surface. They snap ten cubes together to compose as many tens as possible. There are likely to be extra ones.

Tell students to turn to the ladybugs picture in their student book. What is an efficient way to find the total number of ladybugs? We could count groups of 10.

Students use the Tens and Ones removable to record their work. As they work, ask questions such as these:

We could count by fives. Have students circle groups to compose as many groups of 10 as they can. EM2_0105TE_A_L03_classwork_studentwork_CE.indd 17

How do you know you composed as many tens as you can? There are only 4 ladybugs left. I can’t make another group of 10. Have students use their Tens and Ones removable to record their work in unit form, and to record the total number of ladybugs in the number bond. Look at the total. What digit is in the tens place?

25/01/21 10:55 PM

• How do you know you composed all of the tens? • What digit is in the tens place? • What digit is in the ones place? • What is the value of the digit How do you know?

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EUREKA MATH2

What is the value of 2 in 24? How do you know? 20 There are 2 tens. 10, 20. What digit is in the ones place? 4

What is the value of 4 in 24? How do you know? 4 There are 4 ones. 1, 2, 3, 4. Ask students to complete the parts of the number bond to show the value of each digit.

20 2

tens

4 4

ones

Repeat the process for the feathers and the peanuts.

Problem Set Differentiate the set by selecting problems for students to finish independently within the timeframe. Problems are organized from simple to complex.

EM2_0105TE_A_L03_removable_tens_and_ones_studentwork2_CE.indd 15

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Directions may be read aloud.

Land Debrief

5 min

Objective: Recognize the place value of digits in a two-digit number. Display the picture of candles. State and record the number of tens and ones in the picture in unit form. Are all of the tens composed? How do you know? No, there are 11 extra candles. We could compose another ten. 52

Promoting the Standards for Mathematical Practice

As students relate the digits in a number to a representation of that number with all of the tens composed, they look for and make use of structure (MP7). The digits in a number always represent the number in its most composed form. Students need experience representing numbers that have different quantities of tens and ones to prepare them for adding and subtracting with larger numbers later in grade 1 and throughout grade 2.

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EUREKA MATH2

Display the second candle image. How many tens do you see now? How many extra ones do you see? 2 tens, 1 one (Write the number of tens and ones in unit form.)

tens

ones

We can write digits to represent the total as a number. When there are tens and ones, we write a digit in the tens place and a digit in the ones place. Invite students to think–pair–share about the number that shows 2 tens 1 one. Teacher Note What number can we write to represent 2 tens 1 one? 21 Record the total number of candles below the unit form. What is the value of each digit in 21? How do you know? The 2 means 20. We made 2 tens. The 1 in the ones place means there was 1 extra candle. Draw a number bond to record 20 and 1 as parts of 21.

Exit Ticket

Grouping amounts to make different units is whimsically portrayed in the picture book entitled One is a Snail, Ten is a Crab: A Counting by Feet Book, written by Sayre and Sayre. A wide range of critters on the beach have their feet counted in all sorts of combinations, including crabs with 10 legs. Consider using this book as a read-aloud to complement the lessons in this topic.

5 min

Provide up to 5 minutes for students to complete the Exit Ticket. It is possible to gather formative data even if some students do not complete every problem.

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EUREKA MATH2

Sample Solutions Expect to see varied solution paths. Accept accurate responses, reasonable explanations, and equivalent answers for all student work.

Name

2. Circle more groups of 10.

1. Circle all the groups of 10.

tens

Total

ones

tens

Total

tens

Total

tens

Total

ones

26 6

ones

tens

Total

PROBLEM SET

ones

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EUREKA MATH2

3. Circle all the groups of 10.

5. Draw the number with tens and ones.

Show the total with a number bond or a number sentence. Sample:

44 40

10 10 10 30 + 7 = 37

4 58

tens

ones

4. Circle more groups of 10.

50 8

31 10

30 3

tens

1 60 + 4 = 64

one

PROBLEM SET