PARTS OF NATURAL NUMBERS  2

PROBLEMS

To see the answer, pass your mouse over the colored area.
To cover the answer again, click "Refresh" ("Reload").
Do the problem yourself first!

11.  Numbers that end in 0's.  How much is

 a)  A third of 180?  60 b)  A third of 1,800?  600 c)  A fourth of 360?  90 d)  A fourth of 36,000?  9,000 e)  A fifth of 2500?  500 f)  A fifth of 2,500,000?  500,000 g)  A fifth of 200?  40 h)  A fifth of 2,000?  400 i)  An eighth of 400?  50 j)  An eighth of 4,000?  500

12.  How much is

 a)  A third of \$1.20?  \$.40 b)  A fourth of \$2.80?  \$.70 c)  A fifth of \$4.50?  \$.90 d)  A third of \$2.40?  \$.80 e)  An eighth of \$4.00?  \$.50 f)  A sixth of \$3.00?  \$.50 g)  A ninth of \$7.20?  \$.80 h)  A fifth of \$2.00?  \$.40

13.  Increase or decrease by a part.  Last week a blouse cost \$36.
13.  This week the price was reduced by a quarter.  What is the price this
13.  week?   \$27

14.  A photograph measures 9 inches by 12 inches.  If it will be enlarged
13.  by a third, what are the new dimensions?

12 inches by 16 inches.

15.  In 1990, the population was 30,000.  By the year 2000, the population
12   had increased by a fifth.  What was the population in 2000?

36,000

16.  Janet used to earn \$28,000 a year.  In her new job, she makes one
28.  quarter more.  How much does she make in her new job?  \$35,000

17.  A mixed number of times.  If tomatoes costs \$.60 a pound, and
14.  you buy three and a half pounds, how much do you pay?  \$2.10

18.  How much is

18.  a)  Two and a half times 40?  100

18   b)  One and a half times 12?  18

18.  c)  One and a quarter times 20?  25

18.  d)  Two and a quarter times 8?  18

18.  e)  Three and a half times 10?  35

18.  f)  Five and a third times 6?  32

15.  g)  One and a quarter times 100?  125

15.  h)  One and three quarters times 100?  175

19.  Finding a part by decomposing.  Complete the following.

19.   a)  Half of 46 = Half of + Half of =

18.   b)  Half of 58 = Half of 50 + Half of 8 = 25 + 4 = 29

19.   c)  Half of 112 = Half of 100 + Half of 12 = 50 + 6 = 56

19.   d)  A third of 72 = A third of 60 + A third of 12 = 24

19.   e)  A third of 690 = A third of 600 + A third of 90 = 230

19.   f)  An eighth of \$42.40 = An eighth of \$40 +

19.  f)  An eighth of \$42.40 = An eighth of \$2.40 = \$5.30

10.  Can you calculate a third of each one mentally?  How much is two
10.  thirds?

10.   a)  42

42 = 30 + 12.  One third = 10 + 4 = 14.  Two thirds = 28.

10.   b)  195

195 = 180 + 15. One third = 60 + 5 = 65. Two thirds = 130.

11.   c)  234  78; 156  d)  \$22.50  \$7.50; \$15.00

11.   e)  \$14.40  \$4.80; 9.60  f)  \$31.20  \$10.40; \$20.80

11.   Calculate mentally by decomposing.

 a)  A fourth of \$9.20 = \$2.30 b)  A fifth of \$28.50 = \$5.70 c)  A fifth of \$17 = \$3.40 d)  A fourth of \$18 = \$4.50 e)  A fourth of \$112 = \$28 f)  A fifth of \$135 = \$27 g)  A sixth of \$138 = \$23 h)  An eighth of \$51.20 = \$6.40

12.   Write a tenth of each of the following.   Write a hundredth.

 45 27.6 8 0.8 600 \$295 \$50 4.5 2.76 0.8 0.08 60 \$29.50 \$5.00 0.45 0.276 0.08 0.008 6 \$2.95 \$.50

13.  Calculator problems

13.  a)  Two thirds of 82,317 = 54,878

13.  b)  Three fourths of \$318.56 = \$238.92

13.  c)  Four fifths of \$893.50 = \$714.80

13.  d)  Five eighths of \$5,045.33 = \$3,153.33

14.  a)   How many ounces are there in half a pound?
14. a)   (1 pound = 16 ounces)  8 ounces

14.  b)  How many ounces are in a quarter of a pound?  4

14.  c)  How many in three quarters of a pound?  12

14.  d)  How many ounces are in an eighth of a pound?  2

14.  e)  How many in seven eighths of a pound?  14

15.  a)  How many ounces are there in a quarter of a cup?

15.  a)  (1 cup = 8 ounces)  2 ounces

15.  b)  How many ounces are in three quarters of a cup?  6

 c)  How many in a third of a cup? 2 23 c) See Example 9 of Lesson 11:  Inexact division.

16.  a)  How many centimeters (cm) are there in a tenth of a meter?

16.  a)  (1 m = 100 cm)   10

16.  b)  How many centimeters are in a quarter of a meter?  25

16.  c)  How many centimeters are in a fifth of a meter?  20

16.  d)  How many in three fifths of a meter?  60

17.   How many feet are there in three quarters of a mile?

17.  (1 mile = 5,280 feet)   3,960

18  How many yards are there in nine tenths of a mile?

18.  (1 mile = 1,760 yards)  1,584

19.  Percent

19.  a)  What number is a third of 100?
13.  a)  (It is not a whole number. Calculate the answer as a mixed
13.  a)  number with a fraction.)

 33 13
 b)  How much is two thirds of 100? 66 23
 c)  What percent means a third? 33 13 %

19.  d)  How much is a third of \$21?  \$7

 19.     e)  How much is 33 13 % of \$21?  \$7
 19.     f)  How much is 66 23 % of \$21?  \$14

20.  Calculator problem.  Round off to two decimal digits.

20.  a)  A sixth of the class got A.  What percent got A?

100 ÷ 616.67%

20.  b)  A seventh of the class got B.  What percent got B?  14.29%

20.  c)  Three eighths of the class got C.  What percent got C?  37.5%

Continue on to the next section.

or