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Chapter 1
The Whole Numbers
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall.
1.6
Multiplying Whole
Numbers and Area
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall.
Multiplying Whole Numbers
Multiplication is repeated addition but with different
notation.

6  30
6+6+6+6+6= 5

factor

factor

product
The  is called a multiplication sign.
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall.
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Properties
Multiplication Property of 0
The product of 0 and any number is 0. For example,
5  0 = 0 and 0  8 = 0.
Multiplication Property of 1
The product of 1 and any number is that same number.
For example,
1  9 = 9 and 7  1 = 7.
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Properties
Commutative Property of Multiplication
Changing the order of two factors does not change their
product. For example,
4  3 = 12 and 3  4 = 12.
Associative Property of Multiplication
Changing the grouping of factors does not change their
product. For example,
(2  3)  4 = 2  (3  4).
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall.
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Properties
Distributive Property
Multiplication distributes over addition. For example,
2(3 + 4) = 2  3 + 2  4
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Example
Rewrite 4(5 + 6) using the distributive property.
4(5 + 6) = 4  5 + 4  6
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall.
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Multiplying Whole Numbers
Example:
Use the distributive property to multiply 3 and 79.
3(79)  3(70  9)
 3  70  3  9
 210  27
 237
Write 79 in expanded form.
Apply the Distributive Property.
Multiply.
Add.
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Multiplying Whole Numbers
Example:
Multiply 624 by 3.
1
624
 3
1872
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Multiplying Whole Numbers
Example:
Multiply 91 by 72.
91
 72
182
6370
6552
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Multiplying Whole Numbers Ending in Zero(s)
Example:
Multiply 3 by 9000.
3  9000 = 3  9 1000
= (27)  1000
= 27,000
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Finding the Area of a Rectangle
Example:
Find the area of the following rectangle.
12 inches
4 inches
12
 4
48 square inches
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Solving Problems by Multiplying
Key Words or
Phrases
Example
Symbols
Multiply
Multiply 3 by 4
34
Product
The product of 5 and 10
5  10
Times
6 times 4
64
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Example
A particular color printer can print 21 pages per minute.
How many pages can it print in 25 minutes?
Pages per minute  Number of minutes
=
21 
25
21
 25
105
420
525 pages
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