Decimals in Money
Objective To provide practice adding and subtracting decimals to
compute balances in a savings account.
c
www.everydaymathonline.com
ePresentations
eToolkit
Algorithms
Practice
EM Facts
Workshop
Game™
Teaching the Lesson
Key Concepts and Skills
• Read and write decimals through
hundredths in the context of money. [Number and Numeration Goal 1]
• Add and subtract decimals through
hundredths in the context of money. [Operations and Computation Goal 2]
• Estimate reasonable solutions for decimal
addition and subtraction problems. [Operations and Computation Goal 6]
• Complete a table of deposits and
withdrawals. [Data and Chance Goal 1]
Family
Letters
Assessment
Management
Common
Core State
Standards
Ongoing Learning & Practice
1 2
4 3
Playing Name That Number
Student Reference Book, p. 254
Math Masters, p. 489
deck of number cards (the Everything
Math Deck, if available)
Students practice representing
numbers in different ways.
Math Boxes 4 6
Math Journal 1, p. 92
Students practice and maintain skills
through Math Box problems.
Ongoing Assessment:
Recognizing Student Achievement
Use Math Boxes, Problem 4. Key Activities
Students read about deposits and
withdrawals in savings accounts and about
interest earned. They use estimation, mental
arithmetic, and paper-and-pencil algorithms
to find account balances.
[Data and Chance Goal 2]
Study Link 4 6
Math Masters, p. 123
Students practice and maintain skills
through Study Link activities.
Curriculum
Focal Points
Interactive
Teacher’s
Lesson Guide
Differentiation Options
READINESS
Finding Totals and Making Change
Math Masters, pp. 114 and 428
coins calculator scissors
Students role-play being salesclerks and
customers using money.
ENRICHMENT
Solving “Goodie Bag” Problems
Math Masters, p. 124
Students apply decimal computation skills
to solve problems involving the contents
and cost of “goodie bags.”
ELL SUPPORT
Building a Math Word Bank
Differentiation Handbook, p. 141
Students add the terms deposit, withdrawal,
and balance to their Math Word Banks.
Key Vocabulary
deposit withdrawal balance interest
Materials
Math Journal 1, pp. 90 and 91
Study Link 45
Math Masters, pp. 427 and 428 (optional)
transparency of Math Masters, p. 122 base-10 blocks (optional) money (optional)
slate
Advance Preparation
Teacher’s Reference Manual, Grades 4–6 pp. 119 –126
266
Unit 4
Decimals and Their Uses
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Getting Started
Mental Math and Reflexes
Math Message
Pose multiplication facts and extended facts.
Suggestions:
Solve Problems 1 and 2 on journal page 90.
4 ∗ 5 = 20
7 ∗ 4 = 28
5 ∗ 5 = 25
3 ∗ 6 = 18
6 ∗ 9 = 54
7 ∗ 5 = 35
8 ∗ 8 = 64
9 ∗ 50 = 450
70 ∗ 8 = 560
60 ∗ 70 = 4,200
50 ∗ 50 = 2,500
Study Link 4 5 Follow-Up
Have partners compare answers. Ask if students used
computation or estimation to solve Problems 5–8. Have
students indicate thumbs-up if they agree with the answers
given by students for Problems 9 and 10.
7 ∗ 9 = 63
1 Teaching the Lesson
Math Message Follow-Up
WHOLE-CLASS
ACTIVITY
(Math Journal 1, p. 90)
Have students share the strategies they used to solve the addition
and subtraction problems. Some students may have modeled the
problems with money or base-10 blocks. Other students may have
used algorithms similar to the ones they use for whole-number
addition and subtraction.
Tell students that in this lesson they will solve more problems
involving the addition and subtraction of money amounts.
Student Page
Introducing Bank Accounts
(Math Journal 1, pp. 90 and 91)
WHOLE-CLASS
ACTIVITY
ELL
Date
LESSON
4 6
䉬
Time
Keeping a Bank Balance
34–37
Math Message
Solve. Show your work on the grid.
Ask students to tell what they know about savings accounts. Have
them read the introduction to “Keeping a Bank Balance” on
journal page 90 and examine the table on page 91. Discuss the
uses of savings accounts. Be sure students understand the terms
deposit, withdrawal, balance, and interest. To support
English language learners, write these terms on the board along
with examples as they are introduced.
Money is put into (deposited into) an account. It can be taken
out of (withdrawn from) the account.
1.
Cleo went to the store to buy school supplies.
She bought a notebook for $2.39, a pen for
$0.99, and a set of markers for $3.99. How
much money did she spend in all?
2.
Nicholas went to the store with a $20 bill. His
groceries cost $13.52. How much change did
he get?
$7.37
$6.48
On January 2, Kate’s aunt opened a bank account for Kate.
Her aunt deposited $100.00 in the account.
Over the next several months, Kate made regular deposits
into her account. She deposited part of her allowance and
most of the money she made babysitting.
Kate also made a few withdrawals—to buy a radio and some
new clothes.
Think about the answers to the following questions:
The bank holds onto the money (the balance) in the account
and keeps track of it.
At regular intervals, the bank adds money to the account
(interest) to pay for the use of the money. The amount of
interest earned depends on the amount of money in the
account—the greater the balance, the more interest earned.
䉬 When you withdraw money, do you take money out or put money in?
䉬 When you deposit money, do you take money out or put money in?
䉬 When your money earns interest, does this add money to your account
or take money away?
The table on the next page shows the transactions (deposits and withdrawals)
that Kate made during the first 4 months of the year and the interest she earned.
Math Journal 1, p. 90
Lesson 4 6
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To support English language learners, also discuss the meanings
of the terms allowance and regular deposits. Summarize by posing
the questions at the bottom of journal page 90.
Practicing Mental Arithmetic
(Math Journal 1, p. 91)
WHOLE-CLASS
ACTIVITY
PROBLEM
PRO
P
RO
R
OB
BLE
BL
LE
L
LEM
EM
SOLVING
SO
S
OL
O
LV
VIN
IIN
NG
Ask students to solve Problems 3 and 4 on journal page 91 using
mental arithmetic. Discuss their solution strategies. One possible
line of reasoning for Problem 3:
No money was withdrawn in January.
Two withdrawals of $16.50 each were made in February for a
total of $33. (Double $16 = $32. Double 50¢ = $1. $32 + $1 =
$33.) This is less than the amount deposited that month.
April deposit: One deposit of $70.60
April withdrawals: Add the dollar amounts: $45 + $27 = $72,
which is more than $70.60. So Kate withdrew more than she
deposited.
Point out how our monetary system uses place value. An amount
like $27.91 can be thought of as 2 ten-dollar bills, 7 one-dollar
bills, 9 dimes, and 1 penny. If $1 is the ONE, then a ten-dollar
bill is ten dollars, a dime is one-tenth of a dollar, and a penny is
one-hundredth of a dollar.
Maintaining a Savings Account
PARTNER
ACTIVITY
(Math Journal 1, p. 91; Math Masters, p. 122)
Student Page
Date
Time
LESSON
Keeping a Bank Balance
4 6
䉬
continued
3.
In March, Kate took more money out of her bank account than she put in.
In which other month did she withdraw more money than she deposited?
4.
Estimate whether Kate will have more or less than $100.00
at the end of April.
5.
Complete the table. Remember to add if Kate makes a deposit
or earns interest and to subtract if she makes a withdrawal.
Date
Transaction
April
Less than $100
Current Balance
$
January 2
Deposit
$100.00
January 14
Deposit
$14.23
⫹
February 4
Withdrawal
$16.50
⫺$
$
$
$
February 11
Deposit
$33.75
⫹$
February 14
Withdrawal
$16.50
⫺$
$
$
$62.00
⫹$
$104.26
⫺$
Interest
$0.78
⫹$
April 1
Deposit
$70.60
⫹$
April 3
Withdrawal
$45.52
⫺$
April 28
Withdrawal
$27.91
⫺$
March 19
Deposit
March 30
Withdrawal
March 31
Using a transparency of Math Masters, page 122, compute the
balance for the first two or three transactions with the class.
Students may suggest several different ways of doing these
computations. They can complete the rest of the table on their
own and check their answers with partners.
$
$
$
$
$
$
100.00
14.23
114.23
16.50
97.73
33.75
131.48
16.50
114.98
62.00
176.98
104.26
72.72
0.78
73.50
70.60
144.10
45.52
98.58
27.91
70.67
Adjusting the Activity
Provide one or two intermediate balances and the final balance on
journal page 91. Have base-10 blocks, coins and bills (Math Masters, page 428),
and a decimal version of the number grid (Math Masters, page 427) available for
students to use.
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 Journal 1, p. 91
268
Unit 4 Decimals and Their Uses
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Student Page
Date
2 Ongoing Learning & Practice
Math Boxes
46
1.
Playing Name That Number
Time
LESSON
PARTNER
ACTIVITY
Solve mentally or with a paper-and-pencil algorithm.
a.
$5.18 - $3.65 =
c.
0.87 + 0.94 =
$1.53
1.81
b.
$16.86 + $9.24 =
d.
11.2 - 3.9 =
$26.10
7.3
(Student Reference Book, p. 254; Math Masters, p. 489)
Students play Name That Number to practice representing
numbers in different ways. See Lesson 2-2 for additional
information.
34–37
2.
Math Boxes 4 6
5.92
INDEPENDENT
ACTIVITY
Put these numbers in order from smallest
to largest.
0.95
9.25
2.95
3.
0.92
0.92 0.95 2.95 5.92 9.25
A trumpeter swan can weigh about
16.8 kilograms. A Manchurian crane can
weigh about 14.9 kilograms. How much
heavier is a trumpeter swan than a
Manchurian crane?
1.9 kilograms
32 33
(Math Journal 1, p. 92)
4.
Mixed Practice Math Boxes in this lesson are paired
with Math Boxes in Lesson 4-9. The skill in Problem 5
previews Unit 5 content.
Writing/Reasoning Have students write a response to the
following: For Problem 3, how many grams heavier is the trumpeter
swan than the Manchurian crane? 1,900 grams Explain what you
did to find your answer. Sample answer: I know that there are
1,000 grams in 1 kilogram. 1.9 ∗ 1,000 = 1,900
Ongoing Assessment:
Recognizing Student Achievement
Math Boxes
Problem 4
Number of items students brought to the
school food drive:
5.
28, 26, 3, 8, 2, 6, 8, 13, 1, 5
How do you write the following number
using digits: six-hundred million, five
thousand, twenty-one? Choose the
best answer.
What is the
28
27
median? 7
a.
maximum?
b.
minimum?
c.
range?
d.
mode?
f.
mean?
e.
6,005,210
1
600,500,021
8
10
600,500,210
600,005,021
73 75
4
Math Journal 1, p. 92
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Use Math Boxes, Problem 4 to assess students’ understanding of data
landmarks. Students are making adequate progress if they can determine the
maximum, minimum, range, mode, and median of the data set. Some students
may be able to calculate the mean.
[Data and Chance Goal 2]
Study Link Master
Study Link 4 6
(Math Masters, p. 123)
Name
INDEPENDENT
ACTIVITY
ELL
Date
STUDY LINK
46
䉬
Rising Grocery Prices
The table below shows some USDA grocery prices for the year 2000
and estimates of grocery prices for the year 2025.
Grocery Item
Home Connection Students solve addition and
subtraction problems that involve grocery prices from the
year 2000 and predicted prices for the year 2025. They
compare prices, compute change, and find total costs.
To support English language learners, discuss the meaning of the
term change in this context.
Time
Price in 2000
Estimated Price in 2025
dozen eggs
$1.02
$1.78
loaf of white bread
$0.88
$3.31
pound of butter
$2.72
$7.36
gallon of milk
$2.70
$5.65
1.
How much more is each item predicted to cost in 2025?
2.
The year is 2000. You buy bread and butter. You hand the
cashier a $20 bill. How much change should you receive?
3.
The year is 2025. You buy eggs and milk. You hand the
cashier a $10 bill. How much change should you receive?
4.
The year is 2000. You buy all 4 items. What is the total cost?
a.
eggs
34 –37
$0.76
b.
bread
$2.43
c.
butter
$4.64
d.
milk
$2.95
$16.40
$2.57
$7.32
5. The year is 2025. You buy all 4 items. What is the total cost? $18.10
6.
If the predictions are correct, how much more will
you pay in 2025 for the 4 items than you paid in 2000?
Sample answers:
7.
Which item is expected to have the greatest price increase?
$10.78
loaf of bread
The price of a loaf of bread in 2000 was $0.88.
The expected price of a loaf of bread in 2025 is $3.31.
This is almost 4 times its cost in 2000.
Explain your answer.
Practice
8.
List the first ten multiples of 3.
9.
List the first ten multiples of 7.
3 , 6 , 9 , 12, 15, 18, 21, 24, 27, 30
7 , 14, 21, 28, 35, 42, 49, 56, 63, 70
Math Masters, p. 123
Lesson 4 6
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Teaching Master
Name
LESSON
4 6
䉬
Date
The table at the right shows different items that
the party store sells to make goodie bags. Use the
information in the table to answer the questions
below. Show or write what you did to solve each
problem.
1.
Time
“Goodie Bags”
Item
Price
erasers
$0.16 each
clay
2 cans for $1.22
key chains
$0.59 each
rubber balls
3 for $0.51
markers
4 packs for $5.60
stickers
$1.39 per pack
whistles
$0.18 each
marbles
$1.41 per bag
gum
3 packs for $1.86
Kareem put a pack of stickers, a rubber ball, and a pack of gum
in each of his goodie bags. What is the cost of each bag?
$2.18
rubber ball: $0.51 3 $0.17; gum: $1.86 3 $0.62;
$1.39 $0.17 $0.62 $2.18
2.
Ella created a bag that cost the same amount as Kareem’s bag but was not
filled with the same things. What did Ella put in her bag?
Sample answer: stickers, clay, and a whistle
clay: $1.22 2 $0.61;
$1.39 $0.61 $0.18 $2.18
3.
Create your own goodie bag. You must place 5 different items in your bag and
the total cost must be between $3.25 and $3.50. Tell what is in your bag and
how much you spent.
Sample answer: eraser, rubber ball, whistle,
marbles, and stickers; $3.31
rubber ball: $0.51 3 $0.17;
$0.16 $0.17 $0.18 $1.41 $1.39 $3.31
Math Masters, p. 124
3 Differentiation Options
PARTNER
ACTIVITY
READINESS
Finding Totals
5–15 Min
and Making Change
(Math Masters, pp. 114 and 428)
To explore adding and subtracting decimals using a concrete
model, have students use money to find totals and make change.
Partners cut apart the item slips and the bills from Math Masters,
pages 114 and 428.
They place the slips facedown in a pile and take turns being
“customer” and “salesclerk.” At each turn:
1. The customer draws two slips and turns them over. These are
the items to be purchased. The customer computes the cost of
the items without using a calculator.
2. The salesclerk uses a calculator like a cash register to find the
total cost.
3. Then the customer gives the salesclerk a $10 bill. The
salesclerk gives the customer the correct change.
ENRICHMENT
Solving “Goodie Bag” Problems
INDEPENDENT
ACTIVITY
30+ Min
(Math Masters, p. 124)
To apply students’ decimal computation skills, have
them solve problems involving the contents and cost
of goodie bags.
ELL SUPPORT
Building a Math Word Bank
PARTNER
ACTIVITY
5–15 Min
(Differentiation Handbook, p. 141)
To provide language support for monetary transactions, have
students use the Word Bank template found on Differentiation
Handbook, page 141. Ask students to write the terms deposit,
withdrawal, and balance; draw pictures relating to each term; and
write other related words. See the Differentiation Handbook for
more information.
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