Percents Practice

7/27/2019 Percents Practice

http://slidepdf.com/reader/full/percents-practice 1/12

33 .

• • • • • • • • • • • • • • • • Work with Percents8 How to

Facts to Know

What Is a Percent?

Percent means “per hundred.” The symbol % also means percent or “per hundred.” Percent is abusiness term going back to the Roman times which is still used to measure interest rates, commissionrates, mark-ups, discounts, and tax rates.

Percent is another way of writing a fraction with a denominator of 100. You can see how decimals,fractions, and percents are three ways of saying the same amount:

0.30 say, “thirty hundredths”

30——100

say, “thirty hundredths”

30% say, “thirty percent,” which means “thirty per hundred”

Changing Decimals to Percents

To change a decimal to a percent, move the decimal point two places to the right and write a % sign.

Sample: Change .16 to a percent .16 = .16 = 16%

Sample: No need to put the decimal point to the right of a whole number.

Sample: Change .4 to a percent .4 = .40 = 40%

Sample: You need to add a zero in order to move the decimal point two places.

Sample: Change .015 to a percent. .015 = .01 5 = 1.5%

Sample: Moving the decimal two places puts it in the middle of 15.

Sample: Change .16 2 –

3

to a percent. .16 2 –

3

= .16 2 –

3

= 16 2 –

3

%

Sample: You don’t need to put the decimal point between the whole number and the fraction.

Changing Percents to Decimals

To change percents to decimals, do the reverse of what you did with the decimal point in changingdecimals to percents—move it to the left.

Sample: Change 6% to a decimal.

Step 1 Remove the % sign.

Step 2 Move the decimal point 2 places to the left. If you don’t see a decimal point, there isan imaginary one to the right of the number.

Step 3 Place zeros in front if necessary.

No matter how many places there are in a number, the rule is the same about moving the decimal.

Samples: 300% = 300. or 3 175% = 175. =

6% = .06 = .06



34


Facts to Know (cont.)

Fractional Percents

A fractional percent is a number such as 1 –3% or 1 –

5%. First change

the fraction to a decimal (See Unit 7). Then follow the same steps

for changing a percent to a decimal.

Changing Percents to Fractions

To change a percent to a fraction, follow these steps:

Sample: Change 30% to a fraction.

Step 1 Remove the percent sign. 30% 30

Step 2 Make the number the numerator of the fraction. 30 30

Step 3 Write 100 for the denominator. 30—100

Step 4 Simplify the fraction, if possible. 30—100

= 3—10

Changing Fractions to Percents

To change a fraction to a percent, follow these steps:

Sample: Change 5 –8

to a percent.

Step 1 Change the fraction to a decimal. Dividethe numerator 5 by the denominator 8.

Step 2 Follow the rules for changing a decimal

to a percent.

Finding a Percent of a Number

To find a percent of a number, change the percent to a fraction or a decimal and multiply.

Sample: Your teacher says that only 4% of two classes totaling 50 students will be awarded ticketsto a baseball game. How many students will receive tickets?

You want to find 4% or 4———100

of 50.

Step 1 Change 4% to a fraction or to a decimal.

Step 2 Multiply 50 by the fraction 4———100

or thedecimal .04.

The final answer is 2 tickets because 4% of 50 is 2.

.6255 –8

= 8 5.000 – 4 800

200 – 160

40 – 40

= 62.5%

1 –3

% = .3% = .003

1 –

5

% = .20% = .0020

As a fraction 4% = 4—100

(or)

As a decimal 4% = .04

4————100

x50—1

=200———100

= 2 or .04 x 50 = 2



35 .



Finding a Percent of a Number and Rounding

Percent is often used in connection with money, but money in the United States has only two decimalplaces. When a money answer has more than two decimal places, round off the answer to the nearestcent.

Sample: Find 12% of $14.70.

Step 1 Change 12% to a decimal. 12% = .12

Step 2 Multiply $14.70 by .12.

Step 3 Round to the nearest cent.

Since 4 is in the thousandths place and is less than 5, drop it for the final answer. If the number in thethousandths place were 5 or greater than 5, you would raise the number in the hundredths place.

Finding What Percent One Number Is of Another

To find what percent one number is of another, make a fraction by placing the part—usually the smallernumber— over the whole, which is usually the larger number.

Sample: What percent is 15 of 40?

Step 1 Place the part over the whole and reduce. 15—40

= 3 –8

Step 2 Change the fraction to a percent.

$14.70x .12

2940+ 14700$1.7640

Finding a Number When a Percent of It Is Given

Sometimes you know only the percent of a number that is missing. To find the missing number, changethe percent to a fraction or a decimal. Then divide the amount you have by the fraction or decimal.

Sample: The student government of the junior high had a car wash and raised $525. That is 75% of what they need to purchase a sound system for the cafeteria. How much do they need?

Step 1 Change 75% to a fraction or change 75% to a decimal.

Step 2 Divide $525 by the fraction or divide $525 by the decimal.

15—40 = 3 –8 x 100———1 = 300———8 = 75—2 = 37 1 –2 %

$700.

.75 $525.00 – 525.00

0

75% = 75—100

= 3 –4

75% = .75

175

1

= $ 1.76

or$525 ÷ 3 –4

= $525—1

x 4 –3

= $700



36

• • • • • • • • • • • • • • Working with Percents8 Practice

1. .07 = _____

2. .75 = _____

3. .035 = _____

4. .33 1 –3

= _____

5. .9 = _____

6. 1.5 = _____

7. .004 = _____

8. .65 = _____

9. .1 = _____

10. .66 2 –3

= _____

Directions: Change the percents to decimals.

11. 9% = _____

12. 35% = _____

13. 4.8% = _____

14. 22 2/9% = _____

15. 60% = _____

16. 125% = _____

17. .3% = _____

18. 95% = _____

19. 20% = _____

20. 33 1/3% = _____

Directions: Change the percents to fractions.

21. 75% = _____

22. 40% = _____

23. 5% = _____

24. 80% = _____

25. 6% = _____

26. 9% = _____

27. 8% = _____

28. 20% = _____

29. 35% = _____

30. 86% = _____

Directions: Change the fractions to percents.

Directions: Find the number when the percentis given.

31. 3 –8

= _____

32. 1 –3

= _____

33. 2 –5

= _____

34. 7 –8

= _____

35. 2 –3

= _____

36. 1 –5

= _____

37. 1 –2

= _____

38. 1 –8

= _____

39. 1—20

= _____

40. 1 –4

= _____

Directions: Find the percent of a number.

41. 17 is what percent of 340? ________





46. 16 is 20% of what number? ________

47. 63 is 70% of what number? ________

48. 70 is 110% of what number? ________

49. 13 is 10% of what number? ________

50. 12 is 14% of what number? ________

Directions: Change the decimals to percents.



37 .

• • • • • • • • • • • • • • • • • Calculate Percents9 How to

Calculating Interest

To find simple interest, use the formula I = PRT

Sample: How much would a loan of $500 be at 6% interest for 6 months?

Step 1 Use the interest formula. The formula to calculate interest is this:Interest = Principal x Rate of Interest x Time (I = P x R x T)

Step 2 Change the rate, given as a percent, to a fraction and reduce. Set up time as afraction of a year.

R = 6———100

= 3—50

T = 6—12

= 1 –2

Step 3 Multiply principal x rate x time. Cancel where possible.

I = 500—1

x 3—50

x 1 –2

= $15

You can also change the percent to a decimal (6% = .06) and the time to a decimal

(6 months = 6—12

= .5) and then multiply.

I = $500.00 x .06 x .5 = $15

Facts to Know

When money is borrowed, you must pay to use it because someone else is losing an opportunity to useit while you have it. What you pay to use the money is called interest . The rate of interest is a percent.The money you borrow is called the principal. Simple interest is paid only on the principal.

The Interest FormulaTo calculate the amount of simple interest on a loan, use this formula:

Interest = Principal x Rate of Interest x Time (or) I = PRT

Rate of Interest

The rate of interest is always given as a percent. You often see rates of interest on loans andinvestments posted outside of banks.

Time

Time in connection with loans is always expressed in years or parts of a year.

1 month = 1—12

of a year 6 months = 6—12

or 1 –2

year

510

1 1



38

• • • • • • • • • • • • • • • • • Calculate Percents9 How to


Calculating Interest (cont.)

Sample: A T-shirt costs $24.99 and a pair

of jeans costs $34.99. Each is on sale for25% off the original price. If Jennabought the T-shirt and jeans while theywere on sale, what was her total pricebefore adding tax? What is the totalamount that Jenna had to pay for her pur-chase after tax was added? (Tax is 8%.)

one-day pass

one-day passtwo-day pass

Discounts and Sales

A discount is used by manufacturers and merchants to mean taking off a certain percentage of the pricegiven in a price list. This price is called the list price. The list price less the discount is known as thenet price. The noun “discount” can be used as a verb, too—“We’re discounting by 15% the list priceon all new cars and trucks during our storewide ‘Get into Spring’ sale!”

You would ask “What’s the discount?” but not, “What’s the sale?” Often you have to figure out yourown savings during a sale, and this is where understanding decimals and percents comes in handy.

Let’s say, for instance, you read that a local amusement park is offering a single, one-day pass to allrides for $12.50, or a special two-day pass for $20.00. You do some quick decimal arithmetic.

$12.50x 2

$25.00

So your savings on a two day pass is the following:

$25.00 – $20.00

$5.00

But, just curious—what percent off is that?

$5.00 = x invert and multiply $5.00 x 100 = 500 or 20% off $25.00 100 $25.00 x 25

Jenna paid $18.74 + $26.24 = $44.98 for the T-shirt and jeans.



48

• • • • • • • • • • • • • • • • • • • • • • Answer Key

20. 0.15; 0.51; 5.01;50.1

21. 4

22. 27

23. 21

24. 5.6

25. 0.2

26. 7.6

27. 18.7

28. 304.81

29. 1.06

30. 27.39

31. 356.14

32. $13.02

33. $163.76

34. 4,567.83

Page 27

1. 2.7

2. .14

3. 4.3384. 1825.2

5. 4121

6. 6

7. 150.9

8. 10.625

9. 1.628

10. 31.88

11. .056

12. .00702

13. .084

14. 599.104

15. 161.505

16. 2.16408

17. 56.088

18. 48.708

19. 7.616

20. .18446

21. 1.8

22. 53

23. 145

24. .091

25. 112.34

26. .922

27. 524.75

28. 893,15529. 0.23

30. 1679.45

Page 28

1. $93.96

2. $4.47

3. $105.30

4. $69.93

5. $53.38

6. $420.52

7. $585.39

8. $256.50

9. 2.646

10. 1.872

11. 2.6628

12. 0.00228

13. $6.30

14. 4.78

15. 137.74

16. $1.38

17. $8.37

18. .1218

Page 32

1. 5

2. 0.139

3. 10.80

4. 625

5. 0.013

6. 0.04

7. 0.038. 750

9. 175

10. $81.25

11. 5.7

12. .043

13. 4.9

14. 80

15. 50

16. 7/20

17. 8/125

18. 3 2/5

19. 3 1/820. 18 1/3

21. 4 5/8

22. 21/2500

23. 66 3/4

24. 159/500

25. 1/16

26. 4 1/4

27. 1 1/10

28. .8

29. .37 1/2 or .375

30. .66 2/3

31. .77 7/9

32. .83 1/3

33. .62 1/2 or .625

34. .33 1/3

35. .7

Page 36

1. 7%

2. 75%

3. 3.5%

4. 33 1/3%

5. 90%

6. 150%

7. .4%

8. 65%

9. 10%

10. 66 2/3%

11. .09

12. .35

13. .048

14. .22 2/9

15. .6

16. 1.25

17. .003

18. .95

19. .2

20. .33 1/3

21. 3/4

22. 2/5

23. 1/20

24. 4/525. 3/50

26. 9/100

27. 2/25

28. 1/5

29. 7/20

30. 43/50

31. 37.5%

32. 33 1/3%

33. 40%

34. 87.5%

35. 66 2/3%

36. 20%37. 50%

38. 12.5%

39. 5%

40. 25%

41. 5%

42. 600%

43. 20%

44. 16 2/3%

45. 25%

46. 80

47. 90

48. 63.6

49. 130

50. 85.71

Page 39

1. $45.00

2. $45.42

3. $10.00

4. $30.00

5. $135.00

6. $73.75

7. $19.90

8. $9.12

9. $298

10. $54.08

Page 40

1. $42.29

2. $196

3. $16.20

4. $0.25

5. $1372.70

Pages 41 and 42

1. 24 pieces of pie

2 1/4 yard

3. 4 miles4. 1 1/8 miles

5. 2 1/2 pieces of taffy

6. 3 weeks

7. 75 ounces

8. 66 1/4 inches

9. $287.65

10. $21.79

11. $114.26

12. $81.16

13. $300; $90; $210

14. $26.45

15. 25 students16. 150 children

17. 20 homes

18. 225 cards

19. $0.87

20. $1.50

21. 26 minutes

22. 288 boxes

23. 6 pounds

24. 6.25%

Pages 43 and 44

1. $500 every sixmonths. Take asalary of $10,000for Sample:

1st year: $5,000 +$5,500 = $10,500

vs. $10,0002nd year: $6,000+ $6,500 =$12,500 vs.$12,000

2. about 18,000miles

3. house numbers

4. $0.20

5. 100%

6. Choco-Chunk andNuts to U areequal in value.Goodie Two-

Shoes is the betterbuy.

7. 200 miles a day

8. $4,250.00

9. $1.25 to breakeven; $4.38 tomake $25,000.

10. a. $14.00

b. $42.00

c. $52.50

d. $87.50

e. $49.00

f. $105.00

Yes, he saved$350.00

11. b

12. a

13. a

14. a

15. After 31 years,the system willstill be worth$10!

16. 52 bushels of wheat, 55 bushelsof corn, and 34bushels of oats.

.5 0 1 – 2 5 0 %

Chart

1. 1—10

, .10, 10%

2. 1 –4

, .25, 25%

3. 9—20

, .45, 45%

4. 3—20

, .15, 15%

5. 4—5

, .80, 80%

6. 5—6

, .833, 83.3%

7. 77——100

, .77, 77%

8. 1—20

, .20, 20%

9. 11—50

, .222, 22%

10. 2 –5

, .40, 40%



Unit 4: Probability, Percent, and Proportion

Name _____________________________________

Percent 1

Directions: Set up each proportion and solve. Write a “therefore statement” for eachsolution.

92



93

Unit 4: Probability, Percent, and Proportion

Percent 1 (cont.)



Appendix B: Answer Keys

Guided Practice Book Answers



40

1. 1—10

2. .25

3. 45%

4. 15%

5.

4

—5

6. 5—6

7. .77

8. 1—20

9. .222

10. 40%

• • • • • • Calculating Fractions, Decimals,and Percents

9 Practice

Directions: Some states require that out-of-state businesses pay a shipping tax to send goods to stateresidents. Refer to this table to do the problems below. (Note: The shipping rates do not reflect theactual current rates.)

Some States’ Shipping Taxes

Alabama . . . . . . . . . . . . . . . AL . . . . . . . 8.00%Maryland . . . . . . . . . . . . . . MD . . . . . . . 5.75%

Georgia. . . . . . . . . . . . . . . . GA . . . . . . . 4.00%

Illinois . . . . . . . . . . . . . . . . . IL. . . . . . . . 2.00%

Indiana . . . . . . . . . . . . . . . . IN . . . . . . . 5.00%

Kentucky . . . . . . . . . . . . . . KY . . . . . . . 6.00%

Missouri . . . . . . . . . . . . . . . MO . . . . . . . 5.725%

1. Miguel lives in Maryland and purchased a sweater for $39.99 from a catalog. Add the shippingtax. What’s the total cost of the sweater? __________

2. Mr. and Mrs. Wong paid a total of $200.00 for an entertainment center for their home in Chicago,Illinois. The salesperson said that there was already a 2% shipping tax already added to the finalprice. What was the price of the entertainment center before the tax was added? __________

3. Stuart lives in Alabama and recently joined a book club that will send a book to him every month.The books are $15.00 each. The book club billing will include the shipping tax. What is the totalamount that Stuart will have to pay for each book? __________

4. The Middlebury High School band in Indiana is going to sell holiday ornaments to raise moneyfor uniforms. Each ornament will cost $5.00. How much is the shipping price per ornament?__________

5. The Williams family live in Lexington, Kentucky. They recently purchased a computer for

$1,295.00. What is the total price for the computer after the shipping tax was added? __________Directions: Complete the table below.

Fraction Decimal Percent



48

• • • • • • • • • • • • • • • • • • • • • • Answer Key

20. 0.15; 0.51; 5.01;50.1

21. 4

22. 27

23. 21

24. 5.6

25. 0.2

26. 7.6

27. 18.7

28. 304.81

29. 1.06

30. 27.39

31. 356.14

32. $13.02

33. $163.76

34. 4,567.83

Page 27

1. 2.7

2. .14

3. 4.3384. 1825.2

5. 4121

6. 6

7. 150.9

8. 10.625

9. 1.628

10. 31.88

11. .056

12. .00702

13. .084

14. 599.104

15. 161.505

16. 2.16408

17. 56.088

18. 48.708

19. 7.616

20. .18446

21. 1.8

22. 53

23. 145

24. .091

25. 112.34

26. .922

27. 524.75

28. 893,15529. 0.23

30. 1679.45

Page 28

1. $93.96

2. $4.47

3. $105.30

4. $69.93

5. $53.38

6. $420.52

7. $585.39

8. $256.50

9. 2.646

10. 1.872

11. 2.6628

12. 0.00228

13. $6.30

14. 4.78

15. 137.74

16. $1.38

17. $8.37

18. .1218

Page 32

1. 5

2. 0.139

3. 10.80

4. 625

5. 0.013

6. 0.04

7. 0.038. 750

9. 175

10. $81.25

11. 5.7

12. .043

13. 4.9

14. 80

15. 50

16. 7/20

17. 8/125

18. 3 2/5

19. 3 1/820. 18 1/3

21. 4 5/8

22. 21/2500

23. 66 3/4

24. 159/500

25. 1/16

26. 4 1/4

27. 1 1/10

28. .8

29. .37 1/2 or .375

30. .66 2/3

31. .77 7/9

32. .83 1/3

33. .62 1/2 or .625

34. .33 1/3

35. .7

Page 36

1. 7%

2. 75%

3. 3.5%

4. 33 1/3%

5. 90%

6. 150%

7. .4%

8. 65%

9. 10%

10. 66 2/3%

11. .09

12. .35

13. .048

14. .22 2/9

15. .6

16. 1.25

17. .003

18. .95

19. .2

20. .33 1/3

21. 3/4

22. 2/5

23. 1/20

24. 4/525. 3/50

26. 9/100

27. 2/25

28. 1/5

29. 7/20

30. 43/50

31. 37.5%

32. 33 1/3%

33. 40%

34. 87.5%

35. 66 2/3%

36. 20%37. 50%

38. 12.5%

39. 5%

40. 25%

41. 5%

42. 600%

43. 20%

44. 16 2/3%

45. 25%

46. 80

47. 90

48. 63.6

49. 130

50. 85.71

Page 39

1. $45.00

2. $45.42

3. $10.00

4. $30.00

5. $135.00

6. $73.75

7. $19.90

8. $9.12

9. $298

10. $54.08

Page 40

1. $42.29

2. $196

3. $16.20

4. $0.25

5. $1372.70

Pages 41 and 42

1. 24 pieces of pie

2 1/4 yard

3. 4 miles4. 1 1/8 miles

5. 2 1/2 pieces of taffy

6. 3 weeks

7. 75 ounces

8. 66 1/4 inches

9. $287.65

10. $21.79

11. $114.26

12. $81.16

13. $300; $90; $210

14. $26.45

15. 25 students16. 150 children

17. 20 homes

18. 225 cards

19. $0.87

20. $1.50

21. 26 minutes

22. 288 boxes

23. 6 pounds

24. 6.25%

Pages 43 and 44

1. $500 every sixmonths. Take asalary of $10,000for Sample:

1st year: $5,000 +$5,500 = $10,500

vs. $10,0002nd year: $6,000+ $6,500 =$12,500 vs.$12,000

2. about 18,000miles

3. house numbers

4. $0.20

5. 100%

6. Choco-Chunk andNuts to U areequal in value.Goodie Two-

Shoes is the betterbuy.

7. 200 miles a day

8. $4,250.00

9. $1.25 to breakeven; $4.38 tomake $25,000.

10. a. $14.00

b. $42.00

c. $52.50

d. $87.50

e. $49.00

f. $105.00

Yes, he saved$350.00

11. b

12. a

13. a

14. a

15. After 31 years,the system willstill be worth$10!

16. 52 bushels of wheat, 55 bushelsof corn, and 34bushels of oats.

.5 0 1 – 2 5 0 %

Chart

1. 1—10

, .10, 10%

2. 1 –4

, .25, 25%

3. 9—20

, .45, 45%

4. 3—20

, .15, 15%

5. 4—5

, .80, 80%

6. 5—6

, .833, 83.3%

7. 77——100

, .77, 77%

8. 1—20

, .20, 20%

9. 11—50

, .222, 22%

10. 2 –5

, .40, 40%

Documents

Percents Practice