Fractions, Decimals and Percents

Pre-Skill Check

0.67

4.5

201.53

0.379

8.04

Write each phrase as a decimal in numerical form.

1. Sixty-seven hundredths

2. Four and five tenths

3. Two hundred one and fifty-three hundredths

4. Three hundred seventy-nine thousandths

5. Eight and four hundredths

Decimals to fractions

1. 0.25 =

2. 2.3 =

3. 70.609 =

4. 3.05 =

5. 2.007 =

6. 271.092 =

Any number to the left of the decimal is a whole number.

The number to the right of the decimal is the numerator of the fraction.

The place value of the LAST digit in the number is the denominator.

Ex: 4.75 = 4 751004 75

One

s. Te

nths

Hun

dred

ths

25100

102 3

70 6091000

3 5100

2 71000

27192

1000

Fractions to Decimals

= 0.7

= 0.22

= 0.714…

= 0.375

= 2.75

= 36.8

Any whole number is a number to the left of the decimal.

Divide the denominator into the numerator.

7101.

922. 573.

38

4.

2 3

45.

36456.

9 60

.0

.6

- 546

0

0

6

- 546

4.6669

Ex: =4 4 + 0.66 =

Decimals to Percents

Move the decimal to the right 2 places.

If there are not enough numbers to fill the spaces add a ‘0’ to fill it in.

Turn the Decimals into Percents

1. 0.56 =

2. 0.79 =

3. 0.05 =

4. 0.2 =

5. 0.367 =

6. 2.1 =

0.97 = 0.6

56%79%5%20%36.7%210%

97% = 60%0

Warm Up - 2/4/09

Turn the decimals into fractions.

1. 3.65 =

2. 0.73 =

3. 19.087 =

Turn the Decimals into Percents.

4. 0.71 =

5. 0.3 =

6. 0.08 =

7. 0.276 = 73100

871000

19

71%

30%

8%

27.6% or 28%

65100

3

Percents to Decimals

Move the decimal to the left 2 places.

If there are not enough numbers to fill the spaces add a ‘0’ to fill it in.

Turn the Percents into Decimals

1. 75% =

2. 24% =

3. 3% =

4. 10% =

5. 12.6% =

6. 150% =

32% = 1%

0.750.240.030.1 or 0.10 0.1261.5 or 1.50

0.32 = 0.010

Fractions and Percents

Fractions to Percents

First turn the fractions into decimals.

Then follow the process for turning Decimals into Percents.

Percents to Fractions

First turn the percent into a decimal.

Then turn the decimal into a fraction.

Turn the Fractions into percents.

Turn the Percents into Fractions.

5. 25%

6. 75%

7. 33%

8. 2%

9. 4%

10.50%

Fractions and Percents

3101. 4 52.

9113.

2 44.

= 0.3

= 0.8

= 0.818

= 0.5

= 0.25 =

= 0.75 =

= 0.33 =

= 0.02 =

= 0.04 =

= 0.5 =

251007510033100 2100 4100

50100

510

or

= 30%

= 80%

= 82%

= 50%

Taking a Percent of an Amount.

Khadijah went to a sale at her favorite store. She found a jacket that was 20% off. If the original cost of the jacket was $150. How much money will she save?

20% of 150

150 x 0.20 =

She would save $30.

How much will the jacket cost?

$150 - $30 =

Turn the percent into a decimal and then multiply the decimal by the amount.

30

$120

20% = 0.20 150x 0.20

002

0

1

0

0000

3+

0003

000000

Warm Up – 2/5/09Bestbuy is having a sale. You found the CD you wanted for 30% off. The original cost was $17.95. What is the sale cost of the CD before taxes?

30% of 17.95

17.95 x 0.30 =

You would save $5.39.

5.39

$12.5630% = 0.30

17.95x 0.30

003

5

0

0000

3+

0083

00585

0500

0

122

How much will the CD cost?

$17.95 - $5.39 =

Find the percent of each amount.

Show your Work.

1. 25% of 80

2. 33% of 90

3. 40% of 67

4. 65% of 175

= 20

= 29.7

= 26.8

= 113.75

Topics Covered So far

Decimals to Fractions Fractions to Decimals Decimals to Percent Percent to Decimals Fractions to Percents Percents to Fractions Percent of an amount

PercentsTarget is having a sale on movies. Chris found the movie he wanted at a discounted price. He saved $8 off the original price of $25. What percent of the original price did he save?

What are we looking for?

The percent off.

How do we find that?

First lets look at another problem and come back to this one later.

PercentsIf Chris found the movie for 20% off and the original cost was $25. How much would he save? Remember that 0.20 is the

same as 0.2

To make the multiplication easier use 0.2

20% of $25

25 x 0.20 =

He would save $5.00.

5.00

20% = 0.20

25x 0.22

005

1

Back to our original problem.

Percents

Target is having a sale on movies. Chris found the movie he wanted at a discounted price. He saved $8 off the original price of $25. What percent of the original price did he save?

What are we looking for?

The percent off.

How do we find that?

PercentsWhen we wanted to find the amount of the discount we multiplied the percent off by the original cost.

So to find the percent of the discount we do the opposite.

20% of $25

25 x 0.20 =

You would save $5.00.

5.00

20% = 0.20

25 x ______ = 8What %

If 25 x something = 8 then8÷25 = that same something

For ex: 6 x 4 = 24 so: 24÷6 = 4

44

PercentsTo find the percent of an amount when you know the original cost and the amount of the discount. Divide the discount by the original cost.

So to find the percent of the discount we do the opposite.

25 x ______ = 8What %

If 25 x something = 8 then8 /25 = that same something

For ex: 6 x 4 = 24 so: 24/6 = 4

44

25 80

.0

.3

- 755

0

0

2

- 500

Percents

8/25 = 0.32

0.32 = 32%

So, he is saving 32% off the cost of the movie.

Find the percent of the number

1. 7 is what percent of 35?2. 12 is what percent of 60?3. 50 is what percent of 75?4. 42 is what percent of 84?5. 6 is what percent of 32?

20%

20%

66.7% or 67%

50%

18.7% or 19%

Taking a Percent of an Amount.

Michael went to buy a new video game for his Xbox 360. He found the game he wanted on sale for 35% off. The original cost was $49.99. What is the sale cost of the game before taxes?

35% of 49.99

49.99 x 0.35 =

He would save $17.50.

How much will the game cost?

$49.99 - $17.50 =

Turn the percent into a decimal and then multiply the decimal by the amount.

17.50

$32.49

35% = 0.35 49.99x 0.35

953

7

4

0

0000

4+

9599

05697

4

44

400

1

2

222

1111

Warm Up – 2/6/09

Turn the percents into fractions.

1. 79% =

2. 12% =

3. 56% =

Turn the Decimals into Percents.

4. 2.51 =

5. 0.07 =

6. 0.7 =

7. 0.329 = 12100 56100

251%

7%

70%

32.9% or 33%

791000.79 =

0.12 =

0.56 =