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Teaching the Lesson materials
Key ActivitiesStudents express remainders in division problems as fractions that become part of mixed-number answers or as decimals. They solve other division problems in which the remainder is either rounded up or ignored.
Key Concepts and Skills• Use multiples to solve division problems. [Number and Numeration Goal 3]
• Solve division number stories and interpret remainders. [Operations and Computation Goal 4]
• Use arrays to model division. [Operations and Computation Goal 7]
• Write number models to represent division number stories. [Patterns, Functions, and Algebra Goal 2]
• Write number models containing grouping symbols. [Patterns, Functions, and Algebra Goal 3]
Key Vocabulary mixed number
Ongoing Learning & Practice materials
Students play Division Dash to practice dividing 2- or 3-digit dividends by1-digit divisors.
Students practice and maintain skills through Math Boxes and Study Link activities.
Ongoing Assessment: Recognizing Student Achievement Use journal page 150.[Operations and Computation Goal 2]
Differentiation Options materials
Students read ARemainder of One,create arrays and recordnumber models based on the story.
Students solve a divisionnumber story by findingmultiples.
Students practice solvingdivision problems.
� Teaching Masters(Math Masters,pp. 183 and 184)
� 5-Minute Math,pp. 20 and 25
� A Remainder ofOne
� centimeter cubes;counters (optional)
EXTRA PRACTICEENRICHMENTREADINESS
3
� Math Journal 1,p. 150
� Student ReferenceBook, p. 241
� Study Link Master(Math Masters,p. 182)
� Game Master (Math Masters,p. 471)
� per partnership: 4 each of numbercards 1–9
2
� Math Journal 1, pp. 148 and 149
� Study Link 6�3
� slate
� 13 sticks of gum (optional)
1
Objectives To introduce the expression of remainders as
fractions or decimals; and to provide practice interpreting
remainders in division problems.
Technology Assessment Management SystemMath Boxes, Problem 3
See the iTLG.
Additional InformationAdvance Preparation For the optional Readiness activity in Part 3, obtain the book A Remainder of One by Elinor J. Pinczes (Houghton Mifflin, 2002).
Lesson 6�4 419
See Advance Preparation
420 Unit 6 Division; Map Reference Frames; Measures of Angles
Adjusting the Activity
� Math Message Follow-UpPoint out that 4 R1 is a correct answer to the Math Messageproblem, but that this answer will not satisfy the three studentswho want to know who gets the last piece of gum.
Ask students to draw a simple picture to organize the informationin the problem. Have several volunteers draw their pictures on the board.
Ask: What do the quotient 4 and remainder 1 represent? Eachstudent can have 4 sticks of gum, and 1 stick will be left.Ask: Should the 1 stick be ignored? No. That would be a waste.The context of the problem indicates that the remainder should be made part of the answer.
One way to do this is to divide the remainder among the 3 students. Draw a rectangle to represent one stick of gum and divide it into thirds. Label each section �
13�.
ELL
Act out the problem using actual sticks of gum. Open the thirteenth stick
and break it into 3 equal pieces.
A U D I T O R Y � K I N E S T H E T I C � T A C T I L E � V I S U A L
WHOLE-CLASS ACTIVITY
1 Teaching the Lesson
Getting Started
Study Link 6�3 Follow-Up Have students compare answers. Ask volunteers toshare different ways to solve the problems.
Math MessageThree students share 13 sticks of gum. How manysticks of gum does each student get if they receive equal shares?
Mental Math and Reflexes Pose division facts. Suggestions:
13
13
13
12 � 6 = 2
16 � 4 = 4
30 � 6 = 5
70 � 7 = 10
21 � 3 = 7
32 � 4 = 8
27 � 3 = 9
24 � 6 = 4
72 � 9 = 8
42 � 7 = 6
36 � 4 = 9
63 � 9 = 7
students sticks of gum per student sticks of gum in all
3 ? 13
13 sticks of gum shared
equally by 3 students
13 / 3 = x
13 sticks of gum.
3 students.
3 � x = 13
Lesson 6�4 421
///
////\///
////\///
////\///
////\///
14
14
14
14
14
14
14
14
14
14
14
14
25› 25› 25› 25›
$1.00
Therefore, each student will receive 4�13� sticks of gum. Another
way to say this is 4�13� sticks of gum per student. Explain that 4�
13� is
called a mixed number.
Students can check their answers by multiplying 3 � 4 and addingthe remainder of 1. (3 � 4) � 1 � 13
� Expressing Remaindersas Fractions or DecimalsTell students that in this lesson they will solve division numberstories in which something must be done with the remainder inorder to provide a useful answer. In the following examples, theremainder is expressed as a fraction or decimal.
Ask students to draw a simple picture to organize the informationfor each problem below.
Example 1: Four brothers are given 35 fruit bars. They agree toshare the bars equally. How many fruit bars will each boy get?
This is a division problem: 35 / 4 → 8 R3. If they each get 8 fruitbars, 3 fruit bars would still need to be divided.
Sketch the 3 fruit bars on the board. Divide each into fourths torepresent the 4 boys sharing each bar.
If each boy takes one piece of each bar, he will have 8�34� fruit bars.
Some students will discover the shortcut for writing a remainderas a fraction:
1. Make the remainder the numerator of the fraction.
2. Make the divisor the denominator of the fraction.
Then write the answer as a mixed number in which the remainderis now expressed as a fraction.
In some problems, especially those involving money, it may bepreferable to change the fraction to an equivalent decimal.
Example 2: Four people split the cost of a $15 present equally.What is each person’s share? 15 � 4 → 3 R3.
Using the remainder as the numerator of the fraction and thedivisor as the denominator leads to the answer $3�
34�, or $3.75.
Sketch a dollar bill on the board. Divide it into fourths to showthat �
34� of $1.00 = $0.75.
WHOLE-CLASSACTIVITY
35 fruit bars shared
equally by 4 brothers
35 / 4 = x
Each of the 4 brothers gets �34
�
of the remaining 3 bars.
Links to the FutureIn Unit 7 of Fourth Grade Everyday
Mathematics, students will continue their
exploration of mixed numbers in their work
with number lines, regions, and collections.
422 Unit 6 Division; Map Reference Frames; Measures of Angles
� Interpreting Remainders in Problem ContextsThe remainder in a division number story should not always be converted to a fraction or decimal and retained as part of theanswer. Depending on the situation, the remainder might beignored because it is a leftover amount that cannot be split upfurther. Or, it might indicate that the answer should be roundedup. Discuss examples that illustrate these other situations. Foreach problem, ask students to draw a simple picture to organizethe information.
Remainder that is ignored● Three children wish to divide a set of 16 toy cars equally. What
is each child’s share?
Each child can have 5 cars, and there is 1 car left over. Unlike the1 stick of gum in the Math Message problem that could be cut intoequal parts, the 1 remaining toy car cannot be divided up.Therefore, the remainder is considered a “leftover” amount.
Remainder that is ignored ● Ann has $18 to buy notebooks that cost $4 each. How many
notebooks can she buy?
The division is 18 � 4 → 4 R2. Ann can buy 4 notebooks and willhave $2 left. The remainder can be ignored. Note that Ann willhave $2 left, but the answer to the question is 4 (notebooks).
Remainder that indicates the answer should be rounded up ● Esteban has 29 photographs. He can fit 6 photos on each page
of his photo album. How many pages must he use to hold all 29 photos?
The division is 29 � 6 → 4 R5, or 4�56�. Esteban needs 4�
56� pages to
include all 29 photos. Four pages hold only 24 photos and are notenough. Esteban must use a fifth page to hold the last 5 photos.He must use 5 pages in all, which is 4�
56� rounded up to the next
whole number.
$4 $4
$4 $4$2
WHOLE-CLASSACTIVITY
149
Interpreting Remainders continuedLESSON
6�4
Date Time
3. Lateefah won 188 candy bars in a raffle.
She decided to share them equally with 7 of
her classmates and herself. How many
candy bars did each person receive?
Picture:
Number model:
Answer: candy bars
What did you do about the remainder?
Circle the answer.
A. Ignored it
B. Reported it as a fraction or decimal
C. Rounded the answer up
Why?
evenly among the 8 people.
be cut into halves and shared
remaining 4 candy bars can
Sample answer: The
23�48
� or 23�12
�
188 � 8 ∑ 23 R4
Sample picture:
8 equal groups
188candybars
Write each answer as a mixed number by
rewriting the remainder as a fraction.
4. 2�2�7�
5. 10�8�8�3�
6. 16�2�5�2�
Write each answer as a decimal.
7. 39 � 2 � 19 R1
8. 183 � 12 � 15 R3
9. 2,067 � 5 � 413 R2 413.4
15.25
19.5
15 �11
26�
88 �130�
13 �12
�
Try This
13 R1
88 R3
15 R12
Math Journal 1, p. 149
Student Page
148
Interpreting RemaindersLESSON
6�4
Date Time
1. Jackson is buying balloons for a party.
Balloons cost $6 per bunch. How many
bunches can he buy with $75?
Picture:
Number model:
Answer: bunches
What did you do about the remainder?
Circle the answer.
A. Ignored it
B. Reported it as a fraction or decimal
C. Rounded the answer up
Why?
to buy another bunch.
three dollars left isn’t enough
Sample answer: The
12
75 � 6 ∑ 12 R3
$6 $6 $6 $6 $6
$6 $6
$6 $6
$6 $6 $6
2. Rosa is buying boxes to hold all 128 of her
CDs. Each box holds 5 CDs. How many
boxes are needed to store all of her CDs?
Picture:
Number model:
Answer: boxes
What did you do about the remainder?
Circle the answer.
A. Ignored it
B. Reported it as a fraction or decimal
C. Rounded the answer up
Why?
to store the remaining 3 CDs.
additional box was needed
Sample answer: An
26
128 � 5 ∑ 25 R3
5 5 5 5 55 5 5 5 55 5 5 5 5553
5 5 5 55 5 5 5
For each number story:
� Draw a picture.
� Write a number model.
� Use a division algorithm to solve the problem.
� Decide what to do about the remainder.
179
Sample pictures:
Math Journal 1, p. 148
Student Page
Adjusting the Activity
� Solving Division Problems and Interpreting Remainders(Math Journal 1, pp. 148 and 149)
Encourage students to think about each remainder and thedifferent ways in which it should be interpreted as they completejournal pages 148 and 149.
� Playing Division Dash(Student Reference Book, p. 241; Math Masters, p. 471)
Students play Division Dash to practice dividing 2- or 3-digit dividends by 1-digit divisors.
Use this game variation as appropriate:
Have students place only the 2 and 5 cards in the divisor pile.
A U D I T O R Y � K I N E S T H E T I C � T A C T I L E � V I S U A L
� Math Boxes 6�4(Math Journal 1, p. 150)
Mixed Practice Math Boxes in this lesson are paired with Math Boxes in Lesson 6-2. The skill in Problem 5previews Unit 7 content.
Ongoing Assessment:Recognizing Student Achievement
Use Math Boxes, Problem 3 to assess students’ ability to solve decimal
addition and subtraction problems. Students are making adequate progress if
they compute the correct sums and differences. Some students may be able to
explain how to use ballpark estimates or the relationship between addition and
subtraction to check their answers.
[Operations and Computation Goal 2]
� Study Link 6�4(Math Masters, p. 182)
Home Connection Students practice using a divisionalgorithm and interpreting the remainder.
INDEPENDENTACTIVITY
Math Boxes
Problem 3 �
INDEPENDENTACTIVITY
PARTNER ACTIVITY
2 Ongoing Learning & Practice
PARTNER ACTIVITY
150
Math Boxes LESSON
6�4
Date Time
4. How many centimeters are in 12 meters?
Circle the best answer.
A. 0.12
B. 1.2
C. 120
D. 1,200
5. Circle the fractions equivalent to �1
2�.
�1
8
6� �
5
6� �
1
6
2�
�2
3� �
1
2
2
4� �
1
8
5�
1. Joe ordered 72 plants for his patio garden.
Each pot holds 4 plants. How many pots
are needed to hold all of the plants?
2. Solve each open sentence.
a. (6 � 9) � (3 � A) � 30 A �
b. 24 � 8 � 21 � B B �
c. 72 � (2 � C) � 9 C �
d. 6.2 � 0.79 � D D �
e. 8.91 � E � 2.72 E � 6.196.99
475
pots plants per plantspot in all
? 4 72
35–37148
34–37
51129
3. Use a paper-and-pencil algorithm to add or subtract.
a. 0.37 b. 2.9 c. 6.79 d. 7.80
� 0.26 � 5.01 � 6.55 � 3.65
Number model:
Answer: 18 pots
72 / 4 � 18
0.63 7.91 0.24 4.15�
Math Journal 1, p. 150
Student Page
STUDY LINK
6�4
Name Date Time
Interpreting Remainders
1. Mrs. Patel brought a box of 124
strawberries to the party. She wants to
divide the strawberries evenly among
8 people. How many strawberries will
each person get?
Picture:
Number model:
Answer: strawberries
What did you do about the remainder?
Circle the answer.
A. Ignored it
B. Reported it as a fraction or decimal
C. Rounded the answer up
Why?
2. Mr. Chew has a box of 348
pens. He asks Maurice to
divide the pens into groups
of 16. How many groups
can Maurice make?
Picture:
Number model:
Answer: groups
What did you do about the remainder?
Circle the answer.
A. Ignored it
B. Reported it as a fraction or decimal
C. Rounded the answer up
Why?
to form another group of 16.
aren’t enough remaining pens
Sample answer: There
21
348 � 16 ∑ 21 R12
into halves.
cut the remaining strawberries
Sample answer: You can
15�48
� or 15�12
�
124 � 8 ∑ 15 R4
Practice
3. 68 � 7 � 4. � 74 � 4
5. �46
9
8� � 6. 3��9�5� � 31 R252
18 R29 R5
15 15 15 15
15 15 15 15
161616161616161616161616161616161616161616
Sample picture: Sample picture:
179
Math Masters, p. 182
Study Link Master
Lesson 6�4 423
424 Unit 6 Division; Map Reference Frames; Measures of Angles
LESSON
6�4
Name Date Time
A Remainder of One
Use 25 centimeter cubes to represent the 25 ants in the story A Remainder of One.
1. Divide the cubes into 2 equal rows.
Draw what you did.
How many cubes are in each row?
cubes
How many cubes are left over?
cube(s)
3. Divide the cubes into 4 equal rows.
Draw what you did.
How many cubes are in each row?
cubes
How many cubes are left over?
cube(s)
2. Divide the cubes into 3 equal rows.
Draw what you did.
How many cubes are in each row?
cubes
How many cubes are left over?
cube(s)
4. Divide the cubes into 5 equal rows.
Draw what you did.
How many cubes are in each row?
cubes
How many cubes are left over?
cube(s)0
5
1
8
1
6
1
12
Math Masters, p. 183
Teaching Master
� Exploring Remaindersin Literature(Math Masters, p. 183)
Literature Link To explore the concept of remainders, havestudents read and discuss the book A Remainder of One
by Elinor J. Pinczes (Houghton Mifflin, 2002). For each situationin the story, ask students to create arrays using centimeter cubesand record their work on Math Masters, page 183. Have studentsdescribe the arrays and tell how they determined the number ofrows. Encourage the use of vocabulary from this unit.
� Solving a Multiples Number Story(Math Masters, p. 184)
To apply students’ understanding of multiples, factors,and division and remainders, have them solve a marble-sharing number story. Encourage students tomodel the problem with counters if necessary.
� 5-Minute MathTo offer students more experience with division, see 5-MinuteMath, pages 20 and 25.
5–15 Min
SMALL-GROUP ACTIVITY
EXTRA PRACTICE
5–15 Min
INDEPENDENTACTIVITY
ENRICHMENT
15–30 Min
SMALL-GROUP ACTIVITY
READINESS
3 Differentiation Options
LESSON
6�4
Name Date Time
Multiples Number Story
Paolo has fewer than 40 marbles in a bag. If he splits up the marbles among his 4 friends,
he’ll have 3 left over.
If he divides them among his 7 friends, he’ll have 2 left over.
1. How many marbles are in the bag? marbles
2. Show or explain how you got your answer.
divided by 4. 23 � 4 ∑ 5 R3; 23 � 7 ∑ 3 R2.
2 left over. Only 23 gives a remainder of 3 when it is
divides the marbles evenly among his 7 friends there are
than a multiple of 7 (9, 16, 23, 30, 37) because when Paolo
Sample answer: The number of marbles has to be 2 more
23MARBLES
Math Masters, page 184