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Chapter 2

The Whole Numbers

Chapter 1

Slide 2Copyright © 2015, 2011, 2008 Pearson Education, Inc.

Adding Whole Numbers, and

Perimeter

Section 1.3

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Adding Whole Numbers

An electronics store received a shipment of two boxes of iPods one day and an additional four boxes of iPods the next day. The total shipment in the two days can be found by adding 2 and 4.

The sum (or total) is 6 boxes.2 and 4 are called addends, and the process of finding the sum is called addition.

2 4 6

addend

adden

d sum

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Adding Whole Numbers

To add whole numbers, we add the digits in the ones place, then the tens place, then the hundreds place, and so on.

Add 2236 + 160

Line up numbers vertically so that the place values correspond. Then add the digits in corresponding place values, starting with the ones place.

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Adding Whole Numbers

When the sum of digits in corresponding place values is more than 9, carrying is necessary.

Example: 365 + 89

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Example

Add: 32,285 + 149,761

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Adding Whole Numbers

Addition Property of 0The sum of 0 and any number is that number. For example,7 + 0 = 70 + 7 = 7

Next, notice that we can add any two whole numbers in any order and the sum is the same. For example,4 + 5 = 9 and 5 + 4 = 9.We call this special property of addition the commutative property of addition.

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Adding Whole Numbers

Commutative Property of AdditionChanging the order of two addends does not change their sum.For example,2 + 3 = 5 and 3 + 2 = 5.

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Adding Whole Numbers

Associative Property of AdditionChanging the grouping of addends does not change their sum.For example,3 + (5 + 7) = 3 + 12 = 15 and

(3 + 5) + 7 = 8 + 7 = 15.

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Finding the Perimeter of a Polygon

A polygon can be described as a flat figure formed by line segments connected at their ends.

The perimeter of a polygon is the distance around the polygon. This means that the perimeter of a polygon is the sum of the lengths of its sides.

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Example

Find the perimeter of the polygon.

5 in 8 in

4 in3 in

6 in

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Solving Problems by Adding

Key Words or Phrases

Example Symbols

added to 2 added to 3 2 + 3

plus 5 plus 93 5 + 93

increased by 13 increased by 5 13 + 5

more than 9 more than 30 9 + 30

total the total of 3 and 5 3 + 5

sum the sum of 391 and 3 391 + 3

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Example

The state of Hawaii has 1851 miles of urban highways and 2291 miles of rural highways. Find the total highway mileage in Hawaii. (Source: U.S. Federal Highway Administration)

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ExampleAs years pass, the number of endangered species per country increases. In the following graph, each bar represents a country and the height of each bar represents the number of endangered species identified in that country.

(See graph on the next slide)

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Find the total number of threatened amphibians for Brazil, Peru, and Mexico.