Name ______________________
L ea rn i n g Obj e cti v e
Today, we will multiply decimal numbers.
CFU
What are we going to do today?
Acti va t e ( o r p r o vi de ) P ri o r K n o wl edg e
Multiplication is repeated addition of equal groups.
 A factor is a number used in a multiplication problem.
 The product is the answer to a multiplication problem.
3 factors
 4
12 product
Solve the multiplication problems on your whiteboards.
1.
2 1 5

4
2.
1 2 6

3
CFU
Students, you already know how to multiply with whole numbers. Today, we will use these skills to
multiply decimal numbers.
DataWORKS Educational Research
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©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Co n c e pt D ev el opm e n t
To multiply is to do repeated addition of equal groups.
A decimal number represents a whole number and a part of a whole number
separated by a decimal point.
To multiply decimal numbers:
• Decimal numbers do not need to be lined up by place value.
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiplying Decimal Numbers
Jimmy receives $2.15
every day for allowance.
How much will he have if
he saves his money for
five days?
2.15
2.15
2.15
2.15
+ 2.15
10.75
Jimmy will have $10.75 if
he saves his allowance for
five days.
.
2 1 5

5
1 0 7 5
.
CFU
On your whiteboard, write a decimal number. How do you know it is a decimal number?
Look at the multiplication problem on the right. How many decimal places would there
be on the right in the product?
A 1
B 2
C 3
D 4
2
.
.
4 2 8
 3 1
1 3 2 6 8
Between which two digits would the decimal point be placed in the product?
In your own words, what is the main difference between multiplying whole numbers and decimal numbers?
The main difference is _____________.
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Ski l l Dev el o pm en t /G u i ded P ra cti c e
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
2 1 5
Multiply decimal numbers.
5
Step #1: Multiply the bottom factor with each digit of the top factor. 
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
1.
.
2.
.
1 2 6

6
.
5.
0 decimal places
2 decimal places
.
1 2

8
1 4

7
4.
3.
2 decimal places
1 7 3

5
6.
6 2
 0 4
8 7
 0 6
.
.
CFU
(#2) How did I/you count the total number of decimal places in the two factors?
(#2a) How did I/you place a decimal in the product that many places to the left?
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Ski l l Dev el o pm en t /G u i ded P ra cti c e ( c on t i n u ed)
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
2 1 5
Multiply decimal numbers.
5
Step #1: Multiply the bottom factor with each digit of the top factor. 
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
7.
8.
.
10.
.
.
6 2
 0 4
2 decimal places
.
.
8 7
 0 6
7 3 5 2

2
11.
0 decimal places
9.
.
5 8 1 1

3
2 decimal places
.
.
12.
.
.
4 6 7 1
 0 0 2
2 4 6 3
 0 0 4
CFU
(#2) How did I/you count the total number of decimal places in the two factors?
(#2a) How did I/you place a decimal in the product that many places to the left?
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Rel e va n c e
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
1. Multiplying decimal numbers will help you determine the cost of
multiple items.
$0.51 for 1 pencil sharpener.
$0.51  3 =$1.53
$1.53 for 3 pencil sharpeners.
2. Multiplying decimal numbers will help you convert measurement.
One inch equals 2.54 centimeters. 2.54
x 14
A box is 14 inches long, how
35.56
many centimeters long is it?
The box is 35.56
centimeters long.
3. Multiplying decimal numbers will help you do well on tests.
CFU
Does anyone else have another reason why it is relevant to multiply decimal numbers? (pair-share) Why
is it relevant to multiply decimal numbers? You may give me one of my reasons or one of your own. Which
reason is most relevant to you? Why?
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
Ski l l Cl osu r e
2 1 5
Multiply decimal numbers.

5
Step #1: Multiply the bottom factor with each digit of the top factor.
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
1.
.
2.
2 decimal places
0 decimal places
2 decimal places
.
.
3 2
 0 7
2 6

4
Co n c e pt Cl o su r e
Look at the multiplication problem below. Where would you place the decimal points in the factors if
the product was 1.6892? Explain your answer. Hint: There are multiple answers.
1 0 3
1 6 4
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
Su mm ar y Cl o su r e
What did you learn today about multiplying decimal numbers?
Day 1 ___________________________________________________________________________
________________________________________________________________________________
Day 2 ___________________________________________________________________________
________________________________________________________________________________
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Name ___________________
In d ep en d en t P ra cti c e
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
2 1 5
Multiply decimal numbers.
5
Step #1: Multiply the bottom factor with each digit of the top factor. 
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
1.
.
2.
4.
.
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
2 decimal places
2 9
 0 5
2 3 5

8
5.
7 2 5 4

6
0 decimal places
3.
.
3 6

8
2 decimal places
.
6.
.
.
6 3
 0 8
.
6 5 4 2

0 5
.
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Name ______________________
P eri odi c R evi ew 1
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
2 1 5
Multiply decimal numbers.
5
Step #1: Multiply the bottom factor with each digit of the top factor. 
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
1.
.
2.
4.
.
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
2 decimal places
8 7
 0 6
4 3 9

3
5.
5 8 1 1

3
0 decimal places
3.
.
3 6

2
2 decimal places
.
6.
.
.
3 2
 0 8
.
4 7 2 1

0 8
.
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Name ______________________
P eri odi c R evi ew 2
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
2 decimal places
2 1 5
Multiply decimal numbers.

5
Step #1: Multiply the bottom factor with each digit of the top factor.
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
1.
2.
.
4.
.
5.
.
4 9 2 4

6
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
2 decimal places
3.
4 7 2

x
5
3 6

5
0 decimal places
7 2
 0 7
.
6.
.
.
3 4
 0 3
.
3 5 7 4

0 9
.
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.
Name ______________________
P eri odi c R evi ew 3
To multiply decimal numbers:
• The number of decimal places in the product is equal to the total number of decimal
places in the numbers being multiplied.
Multiply Decimal Numbers
.
.
2 1 5
Multiply decimal numbers.

5
Step #1: Multiply the bottom factor with each digit of the top factor.
(regroup if needed)
1 0 7 5
a. Add regrouped numbers, if any.
Step #2: Count the total number of decimal places in the two factors.
a. Place a decimal in the product that many places to the left.
1.
.
2.
4.
.
6 6 4 3

6
DataWORKS Educational Research
(800) 495-1550 • www.dataworks-ed.com
©2012 All rights reserved.
Comments? feedback@dataworks-ed.com
2 decimal places
5 2
 0 7
2 5 2

7
5.
0 decimal places
3.
.
5 3

3
2 decimal places
.
.
.
6.
4 3
 0 7
.
4 1 3 7

0 6
.
5th Grade Number Sense 2.1 (7Q)
Add, subtract, multiply, and multiply with decimals; add with
negative integers; subtract positive integers from negative
integers; and verify the reasonableness of the results.
Lesson to be used by EDI-trained teachers only.