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7th Grade Math Percents. Relating Fractions, Decimals & Percents Day 1.

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Presentation on theme: "7th Grade Math Percents. Relating Fractions, Decimals & Percents Day 1."— Presentation transcript:

1 7th Grade Math Percents

2 Relating Fractions, Decimals & Percents Day 1

3

4 Order the numbers from least to greatest. 0.15 12.5% 0.095 In order to do this, they must all be in the same form. Let's turn them all into percents: 15% 12.5% 16% 9.5% So least to greatest: 9.5% 12.5% 15% 16% 0.095 12.5% 0.15

5 1Find the lowest value A5% B1/2 C.5% D.05

6 2Find the greatest value A120% B1.02 C.2% D1.19

7 3Find the greatest value A6% B.6 C60 D6

8 4Find the lowest value A2% B.2 C.02 D.2%

9 5Find the lowest value A50% B500% C50.0 D50.01

10 Express each decimal or percent as a fraction in lowest terms: 1) 18% 2) 0.85 3) 4) 5) 5.008 6) 0.0001 Click to Reveal

11 Express each fraction as a percent: 1) 2) 3) Click to Reveal Click to Reveal Click to Reveal

12 6Express as a fraction.

13 7Express as a decimal.

14 8Express as a percent.

15 9Express as a decimal.

16 10Express as a percent.

17 11Express as a percent.

18 Three Types of Percent Problems Day 2

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22 60 = 24.40 Examples: Find 40% of 60 20% of 90.20 90 = 18 Write a mathematical sentence Click

23 X =.10 88 Write a mathematical sentence Try these: Find 12% of 70 What is 40% of 28?

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26 is of % 100 = Note: You can use this box to solve many problems involving percents! Note: Try to find the numbers that are attached to the words/symbols: is, of, or percent.

27 Example: What is 25% of 400? Steps 1. Set up the proportion. 2. Substitute. 3. Solve. is of % 100 = What is 25% of 400? 25 100400 ? Click on each box to see if you substituted correctly. 400 x 25 = 100w 10,000 = 100w 10,000/100 = w 100 = w Click

28 Example: What is 32% of 300? Steps 1. Set up the proportion. 2. Substitute. 3. Solve. is of % 100 = 32 100300 ? Click on each box to see if you substituted correctly. 300 x 32 = 100w 9,600 = 100w 9600/100 = w 96 = w What is 32% of 300? Click

29 Try it: What is 20% of 180? Steps 1. Set up the proportion. 2. Substitute. 3. Solve. is of % 100 =

30 12Find 30% of 45

31 13What is 15% of 90?

32 14Find the greater value. A20% of 16 B10% of 90 C25% of 40 D100% of 7

33 15Find the greater value. A2% of 1000 B5% of 500 C10% of 300 D15% of 100

34 16Identify any values that are equal. AWhat is 40% of 80? B60% of 70 C25% of 128 D200% of 16

35

36 X = 50.40 X = 125

37 Try This: 100 is 20% of what number? 100 =.20 x 100 = x.20 x = 500

38 1756 is 70% of what?

39 1812% of what number is 6?

40 1965% of what number is 10?

41 2027 is 150% of what number?

42 211% of what number is 12?

43

44 What percent of 80 is 24? x 80 = 24 X = 24 80 X =.30 X = 30% Remember, you can solve this by: 1. Translating into an equation 2. Setting up a proportion

45 60 is what percent of 15? 60 = X 15 60 = X 15 4 = X 400% = X

46 22What percent of 3 is 12?

47 2330 is what percent of 36?

48 24What percent of 18 is 180?

49 252 is what percent of 1?

50 26What percent of 25 is 20?

51 You have just studied three different types of percent problems. Try all 3 types: 24 is 40% of what number? 42 is what percent of 840? What is 30% of 45?

52 27Find the largest value. AWhat is 50% of 50? BWhat number is 45% of 60? C30 is 60% of what number? D25% of what number is 150?

53 28Find the greatest percentage value. AWhat percent of 30 is 18? B60 is what percent of 90? CWhat percent of 70 is 210? D1,000 is what percent of 100?

54 29Find 20% of 78.

55 308 is what percent of 28?

56 31What number is 3% of 17?

57 32Find 27% of 54.

58 3323 is what percent of 200?

59 34What percent is 35 of 20?

60 3556% of what number is 40?

61 3645 is 30% of what number?

62 3762% of 40 is what number? A24.8 B.0155 C24.8% D15.5

63 Percent of Change Day 3

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67 Try This! A CD's original price was $12.99. It is now on sale for $10.99. What is the percent of change?

68 Try This! A student's first test grade was 60. The second test grade was an 85. What was the percent of change?

69 38 In 2005, the price of a McDonald's hamburger was $0.89. In 2010, the price of a McDonald's hamburger was $1.19. What was the percent of change?

70 39Original Amount: 500 New: 700 Find the percent of change.

71 40Original Amount: 52 New: 17 Find the percent of change.

72 41The number of students who attended FHS in 2010 was 1405. In 2011, 1380 students attended FHS. What was the percent of change in student enrollment?

73 42Find the percent of change. Original price: $120 Sale price: $75

74 43Find the percent of change. Original price: $80 Sale price: $50

75 44A stereo, originally priced at $360, is on sale for $200. What is the percent of change?

76 Representing Percent Equations Algebraically

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78 Think about this... 100% + 5% = 105% What does that equation look like in decimal form? 1 + 0.05 = 1.05 So, if you increase the price of a shirt 5%, the new price is 105% of the original price. To represent that algebraically, you would write it this way: Let s = the original price of the shirt 1s + 0.05s = 1.05s

79 Example: You sell a shirt for $15.50. This price represents a 5% increase from the price you paid for the shirt. How much did it cost you to purchase the shirt? Let s = the original price of the shirt 1s + 0.05s = 15.50 1.05s = 15.50 s = $14.76 The shirt cost you $14.76.

80 Example: The population of your school decreased by 13% from last year to this year. If there are 957 students in the school this year, how many were there last year? 2 students solved this differently. Who is correct? Why? Is one method easier than the other? Student 1:Student 2: 100% - 13% = 87%1n -.13n = 957 87% of what is 957?0.87n = 957 0.87n = 957n = 1,100 students n = 1,100 students

81 So, what does this mean? m + 0.15m = 1.15m This could mean increase m by 15% or multiply m by 1.15. They mean the same thing! Likewise, what is the meaning of w - 0.42w = 0.58w This means both decrease w by 42% or multiply w by 0.58. Click

82 You Try. 1.A smart phone is on sale for $299, or 18% off. What was the original price of the phone? Write and solve an equation to represent this situation. 2. What does this equation mean? p + 0.02p = 1.02p 3. What does this equation mean? h - 0.1h = 0.9h

83 45Write an equation to represent the problem, then solve. Be prepared to show me your equation! When you go shopping, you must pay an additional 6% in sales tax. What is the price of your items before taxes if your final price is $25?

84 46Choose the equation that represents the situation. The population of a town increased by 1%. Ax + 0.01x = 1.01x Bx + 0.1x = 1.1x Cx - 0.1x = 0.9x Dx - 0.01x = 0.99x

85 47Write an equation to represent the problem, then solve. Be prepared to show me your equation! The number of students in your class has decreased by 12% since September. How many students were there at the start if there are currently 19 students?

86 48Choose the equation that represents the situation. A 15% discount. Ax + 0.15x = 0.85x Bx + 1.5x = 2.5x Cx - 0.015x = 0.985x Dx - 0.15x = 0.85x

87 49Write an equation to represent the problem, then solve. Be prepared to show me your equation! When you paid your bill at a restaurant, you included 24% more to cover tax and tip. If you paid $55.80, what was the amount of the original bill?

88 Applied Percent of Decrease and Increase Day 4

89 Applied Percent of Decrease

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91 When finding a discount, there are two different methods you can use.

92 Example: A $50 sweater is on sale for 20% off. Calculate the sale price. (Discount) (Sale price) (Percent you pay) (Sale price)

93 A manager wants to provide a 30% discount for everything in his store. Find the sale price of a $25 sweater. Using either method, the answer is $17.50 (Discount) (Sale price) (Percent you pay) (Sale price) Click to view Method 1Click to view Method 2 Click to view answer

94 The manager has pants, priced at $45, that he needs to mark down 35%. What will be the sale price of the pants? The pants are on sale for $29.25 (Discount) (Percent you pay) (Sale price) Click to view Method 1Click to view Method 2 Click to view answer

95 Mark wants to purchase a stereo that is on sale, if he is saving at least 30%. The stereo's original cost is $425. What is the most that he is willing to pay for the stereo? (Discount) (Sale price) (Percent you pay) (Sale price) He is willing to pay $297.50 for the stereo. Click to view Method 1 Click to view Method 2 Click to view answer

96 50Decrease 400 by 10%

97 51A $710 computer is to be discounted 30%. What will be the sale price?

98 52A necklace, priced at $120, is to be marked down 15%. What will be the sale price?

99 53The student population of the high school will decrease by 5% next year. The current population is 1407 students. How many students will attend next year?

100 54The store is having a 40% off sale. What percent will the customers pay?

101 55$80 boots are on sale for 20% off. After the sale, the manager raises the price 20%. What will be the selling price of the boots after the sale?

102 Applied Percent ofIncrease

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104 When finding an increase, there are two different methods you can use.

105 Finding a New Amount Increase 55 by 20% (Mark up) (New cost) (Percent you pay) (New cost)

106 Find the new amount Increase 60 by 10% Increase 68 by 12%

107 56Increase 36 by 25%.

108 57Increase 40 by 15%

109

110 Calculate a 20% tip on a $75 bill. What will the customer leave in total? For poor service, my friend will leave a 5% tip. How much less will this waitress earn than the waitress above?

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112 A car costs $23,500. How much sales tax will the customer pay? 23,500(0.07) = $1645 What will the customer pay altogether for the car? 23,500 + 1645 = $25,145 The total cost of the car, including tax, can be calculated as follows: 23,500 +.07(23,500) = 25,145 or 23,500(1.20) = 25,145

113 Discuss: How are tips and sales tax alike?

114 58What is the total cost of a $250 stereo with a 7% sales tax?

115 59Calculate the sales tax on a $125 bicycle.

116 60Mike wants to leave a 20% tip. His bill is $35.50. How much is the tip?

117 61A $65 restaurant tab (bill) is put on the table. The couple plans on leaving an 18% tip. How much should be left altogether?

118 62What is the total cost of a $123 ipod, including tax of 5.5%?

119 Real-Life Application Problems Day 5

120 A store owner pays $12 for a particular bracelet. To cover expenses, the owner will mark up the price by 150%. Find the selling price of the bracelet.

121 The store is having a 20% off sale on all CD's. With the sale, you pay $12 for a CD. What was the original price? A couple left their waiter a 20% tip in the amount of $18. What was the cost of their meal?

122 You and 3 friends had dinner at a restaurant. The cost of their meals is $62. They want to leave a 15% tip. Calculate the tip. When they arrive at the register the cashier will calculate the sales tax on the meal at a rate of 7%. Determine the sales tax. (*Note: You never tax on the tip) Calculate the total cost of the meal for each of you.

123 A store is having a 25% off sale on ipods. You want to purchase an ipod with an original price of $249. The sales tax is 7%, which will be applied to the sale price of the ipod. What is the total cost of the ipod? A computer is on sale for 10% off the original price of $325. When it doesn't sell, the manager marks it down another 20% off the sale price. What is the new sale price of the laptop? Is the new sale price the same as it would be had the manager taken 30% off of the original price? Explain.

124 63Wholesale price: $56 Markup percent: 50% New price ? Wholesale – the cheap price a seller pays for an item they will sell Markup – a percent a seller adds to an item to make a profit. The price a buyer pays.

125 64Tickets cost $7 at the door. If purchased in advance, the tickets cost $5. What is the percent of discount for purchasing tickets in advance?

126 65560 people were surveyed. 25% said they prefer Coke. How many people prefer Coke?

127 66Increase 50 by 25%. What is the new amount?

128 67What is the original price on a pair of boots that sell for $72 after a 25% discount?

129 68An ipod costs $176. It is on sale for 20% off and will be taxed at a rate of 7% on the sale price. What will be the total cost of the ipod?


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