What is Percent of Change?

1
What is Percent of Change?
Common Examples of Percent of Increase Common Examples of Percent of Decrease
Sales tax on an item purchased Items that are on sale at a store
Finding a total bill at a restaurant including tip Population decreases
2
Percent of Change

• Percent of Change the amount, stated as a
  percent, that a number increases or decreases.
• Percent of Increase The amount, stated as a
  percent, that a number goes up.
• Percent of Decrease The amount, stated as a
  percent, that a number goes down.

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Percent of Change

• Percent of Change amount of change
• original
  amount

4
Finding Percent of Change

• 27 is decreased to 20
• 27 20 7
• Percent of Change amount of change
• original
  amount
• Percent of Change 7
• 27
• Percent of Change 0.259259
• Percent of Change 25.9

5
Finding Percent of Change

• 32 is increased to 67
• 67 32 35
• Percent of Change amount of change
• original
  amount
• Percent of Change 35
• 32
• Percent of Change 1.09375
• Percent of Change 109.4

6
Finding Percent of Change

• 20 is decreased to 11
• 20 11 9
• Percent of Change amount of change
• original
  amount
• Percent of Change 9
• 20
• Percent of Change 0.45
• Percent of Change 45

7
Finding Percent of Change

• 42 is increased to 72
• 72 42 30
• Percent of Change amount of change
• original
  amount
• Percent of Change 30
• 42
• Percent of Change 0.71428
• Percent of Change 71.4

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Finding Percent of Change Your Turn

• 24 is increased to 30
• Percent of Change amount of change
• original
  amount

9
Finding Percent of Change Your Turn

• 56 is decreased to 14
• Percent of Change amount of change
• original
  amount

10
Finding Percent of Change Your Turn

• 105 is decreased to 32
• Percent of Change amount of change
• original
  amount

11
Finding Percent of ChangeWord Problems
Zack Cole shot an 86 on the golf course on
Monday. On Friday he shot a 95. What is the
of change?

• 86 increased to 95
• Percent of Change amount of change 9
• original amount
  86

Percent of Change 10.5
12
Finding Percent of ChangeWord Problems
Kelly Dyer became a great writer. She had a
picnic each year to celebrate the date of her
first published work. The 1st year 50 people
came. The 2nd year 30 people came. What is
the percent of change?

• 50 decreased to 30
• Percent of Change amount of change 20
• original
  amount 50
• Percent of Change 40

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Finding Percent of ChangeWord Problems Your Turn

• Last six weeks Joseph Lawhorn made an 88. This
  six weeks he made a 92. Please figure the
  percent of change.

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Finding Percent of ChangeWord Problems Your Turn

• Angela Smyre became a famous architect. She made
  90,000 in 2004. In 2005 she made 120,000.
  What is the percent of increase?

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Finding Percent of ChangeWord Problems Your Turn

• Amber Robinson became a foster mother, because
  she is so good with children. She took care of 8
  children in 2003. In 2004 she had only 5. What
  is the percent of change?

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Using Percent of Change

• When you know the percent of change, you can use
  an equation, or proportion to find the actual
  amount.

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Using Percent of Change

• The regular price of a portable CD player at
  Edwins Electronics is 31.99. This week it is
  on sale for 25 off. Find the amount of the
  discount.
• Part (is) Part
• Original Whole (100)
• x 25
• 31.99 100
• 100x 799.75 x 7.9975 8

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Using Percent of Change

• The regular price of a portable CD player at
  Edwins Electronics is 31.99. This week it is
  on sale for 25 off. Now, Find the sale price.
• x 7.9975 8
• 31.99 - 8.00 23.99
• The sale price is 23.99

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Using Percent of Change

• The retail price of a pair of shoes is a 98
  increase from its wholesale price. If the
  wholesale price is 12.50, what is the retail
  price?
• Part Part
• Original Whole (100)
• x 98
• 12.50 100
• 100x 1225 x 12.25

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Using Percent of Change

• The retail price of a pair of shoes is a 98
  increase from its wholesale price. If the
  wholesale price is 12.50, what is the retail
  price?
• x 12.25
• 12.50 12.25 24.75
• The retail price is 24.75

21
Using Percent of Change

• The regular price of a sweater is 42.99. It is
  on sale for 20 off. Find the amount of the
  discount and sale price.
• Part Part
• Original Whole (100)
• x 20
• 42.99 100
• 100x 859.8 x 8.598 8.60

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Using Percent of Change

• The regular price of a sweater is 42.99. It is
  on sale for 20 off. Find the amount of the
  discount and sale price.
• x 8.60
• 42.99 - 8.60 34.39
• The sale price is 34.39

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Using Percent of ChangeYour Turn

• A backpack that usually sells for 39 is on sale
  for 33 off. Find the amount of the discount and
  the sale price.

24
Using Percent of ChangeYour Turn

• A sporting good store is having a closeout on a
  certain style of running shoes. They are marked
  55 off the regular price. Find the amount of
  the discount and the sale price.

25
Using Percent of ChangeYour Turn

• A gallery owner purchased a very old painting for
  3,000. The painting sells at a 325 increase in
  price. What is the retail price of the painting?