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Today we will review “Percents”

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Let’s Warm up:

1) ¾ x ¼ = 2) 3/5 ÷ 1/4 =

3) 5/6 x 2/5 = 4) ½ ÷ ¾ =

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Modeling Percents A percent (%) is a ratio that compares a number to 100

75% = 75 out of 100 Use a 10 x 10 grid to model percents Example: Model 18%

18% means 18 out of 100 So, shade 18 out of the 100 squares

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Your Turn! Model 75%

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Modeling Percents Identify a percent that is modeled

There are 40 out of 100 squares shaded So, the model shows 40%

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Your Turn! Identify the percent modeled.

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Percents & Fractions All percents can be written as fractions in simplest form

To write a percent as a fraction, Write the percent as a fraction with a denominator as 100 Then simplify

Write 50% as a fraction in simplest form 50% means 50 out of 100

2

1

100

50

100

50%50

2

1

or

Write the percent as a fraction with a denominator of 100

Simplify. Divide the numerator and the denominator by the

GCF, 50

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Percents & Fractions Write 125% as a fraction in simplest form

125% means 125 for every 100

4

11

100

521

100

125%125

4

1

or

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Your Turn! Write 10% as a fraction.

Write 135% as a fraction.

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Percents & Fractions Write a Fraction as a Percent

Write 9/10 as a percent

90% toequivalent is 10

9 So,

Simplifyn 90

10by sideeach Divide 10

10

100

900

Multiply10n 900

products cross then Write x 10 100 x 9

proportion a upSet 100100

9

n

n

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Your Turn! Write 3/5 as a percent

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Percents & Decimals Percents can be written as a decimal To write a percent as a decimal

Rewrite the percent as a fraction with a denominator of 100 Then write the fraction as a decimal

Write 56% as a decimal

Shortcut: Move the decimal point two places to the left, which is the same as dividing by 100

decimal a asfraction the Write0.56

100 ofr denominato aith fraction w a aspercent theRewrite 100

56%56

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Your Turn! Write 0.3% as a decimal

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Percents & Decimals To write a decimal as a percent

Write the decimal as a fraction whose denominator is 100 Then write the fraction as a percent

Write 0.38 as a percent 0.38 = 38/100 Write the decimal as a fraction

= 38% Write the fraction as a percent Shortcut: Move the decimal place two places to the right, which is

same as multiplying by 100

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Your Turn! Write 0.189 as a percent

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Percent of a Number To find the percent of a number

Write the percent as a fraction and then multiply or Write the percent as a decimal and then multiply

Find 5% of 300 Method 1: Write the percent as a fraction

15. is 300 of 5% So,

15or 30020

1300

20

120

1or

100

5%5

of

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Percent of a Number Method 2: Write the percent as a decimal

Use a model to check the answer.

The model confirms that 5% of 300 is 15

15. is 300 of 5% So,

15or 30005.0300 05.0

0.05or 100

5%5

of

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

0 30 60 90 120 150 180 210 240 270 300

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Your Turn! Find 120% of 75.

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Estimating with Percents Sometimes when finding the percent of a number, an exact number is not

needed So, you can estimate Commonly used Percents and their Fraction equivalents

3

1%

3

133

5

1%20

2

1%50

5

4%80

4

1%25

10

3%30

5

3%60

10

9%90

4

3%75

3

2%

3

266

5

2%40

10

7%70 1%100

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Estimating with Percents Estimate 52% of 298

52% is close to 50% or ½ Round 298 to 300 ½ of 300 is 150 So, 52% of 298 is about 150

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Your Turn! Estimate 60% of 27

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Let us take a break!

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Game

Click me

Let us see how much you score on this one!

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Assessment

1. Model 8%

2. Identify the percent modeled.

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Assessment

3. Write 97% as a fraction in simplest form.

4. Write 3/5 as a percent.

5. Write 32% as a decimal.

6. Write 0.47 as a percent.

7. Find 55% of 160.

8. Estimate 48% of $76

9. Ian used 35% of his allowance to buy a book. If Ian received $20 for his allowance, how much did he use to buy the book?

10. Melissa bought a sweatshirt that originally cost $30. If the sweatshirt was on sale for 25% off, what was the discount?

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Good Job! You have learned a lot today!!!