06 Pri WB Math P5.pdf

Mathematics Pratomsuksa 5 Chapter 6 Exercises

50

• Readingandwriting2-decimalplacenumbers

Example: Innumerals Inwords

0.89 zero point eight nine34.56 thirty-four point five six

• PlacevaluesanddigitvaluesofdigitsindecimalsExample:

Placevalue Tens Ones Decimal

point Tenths Hundredths

Digit 4 9 . 1 2Digit value 40 9 .

1—– or 0.1 10

2—— or 0.02 100

• Writingdecimalsinexampledform

Example: 85.37 = 80 + 5 + 0.3 + 0.07

• Comparingandorderingfractions

Example: 9.2 = 9.20 ; 3.4 , 3.46 ; 7.58 . 7.08

Example:

ascending

3.4, 3.46, 7.08, 7.58, 9.2

descending

• Decimalsandfractions

Example: 5.5 = 5 510

= 5 12

; 222100

= 2 22100

= 21150

6 D e c i m a l s

06 Pri Edu WB Math P5.indd 50 2/17/11 9:35:35 AM


51

A Writethedecimalfortheshadedpartsineachdiagram.

1.

0.7

3.

0.37

2.

1.15

4.

1.76

B Shadethediagramforeachdecimal.

1. 0.72 3. 0.09

2. 1.55 4. 1.50



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C Writethefollowingdecimalsinwords.

1. 12.11 twelve point one one 2. 13.31 thirteen point three one

3. 9.01 nine point zero one 4. 7.07 seven point zero seven

5. 81.5 eighty-one point five 6. 99.6 ninety-nine point six

7. 821.99 eight hundred and twenty-one point nine nine

8. 166.52 one hundred and sixty-six point five two

D Writeindecimal.

1. Zero point six 0.6

2. Zero point zero one 0.01

3. Nine point four seven 9.47

4. Fifteen point zero two 15.02

5. Forty point five eight 40.58

6. Ninety-nine point nine nine 99.99

7. One hundred and one point one 101.1

8. One hundred and sixty-six point eight eight 166.88



53

E Statetheplacevaluesandthedigitvaluesoftheunder-lineddigitsinfractionanddecimalforms.

Example:

1. Hundredths 3—–100

0.03

2. Tenths 8—–10

0.8


0.01


0.03

5. Tenths 5—–10

0.5

F Writethefollowingdecimalsinexpandedform.

1. 80.31 80 + 0.3 + 0.01

2. 42.05 40 + 2 + 0.05

3. 513.72 500 + 10 + 3 + 0.7 + 0.02

4. 1,291.38 1,000 + 200 + 90 + 1 + 0.3 + 0.08

5. 2,846.58 2,000 + 800 + 40 + 6 + 0.5 + 0.08



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G Express each of the following expanded forms asdecimals.

1. 30 + 2 + 0.09 32.09

2. 200 + 8 + 0.7 + 0.05 208.75

3. 700 + 50 + 7 + 0.5 + 0.05 757.55

4. 1,000 + 400 + 0.2 + 0.07 1,400.27

5. 1,000 + 10 + 9 + 0.8 1,019.8

H Tick (✓) the correct statements. Cross (✗) the incorrectstatementsandcorrectthem.

1. 10 + 8 + 0.7 is the expanded form of 18.07. ✗

10 + 8 + 0.7 is the expanded form of 18.7.

2. 77.77 = 70 + 7 + 0.07 ✗

77.77 = 70 + 7 + 0.7 + 0.07

3. 0.6 + 0.05 = 0.65 ✓

4. 2,789.33 equals to 2,000 + 700 + 80 + 9 + 0.3 + 0.03. ✓

5. 5 is in the place value of hundredths. Its value is 500. ✗

Its value is 0.05



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I Circlethedecimalsthathavegreatervaluesoftheunder-lineddigits.

1. 66.06 56.61 4. 111.11 312.01

2. 502.56 161.57 5. 202.02 123.23

3. 700.82 113.20 6. 860.7 985.07

J Fillinthe>,<or=intheboxes.

1. 1.2 < 2.2 6. 19.08 < 19.8

2. 6.18 < 8.61 7. 110.10 > 101.01

3. 10.2 > 10.12 8. 123.32 < 132.23

4. 1,009.90 < 1,009.99 9. 280.14 < 280.41

5. 0.03 < 3.00 10. 44.57 > 44.52

K Arrange the following sets of decimals in the ordersmentionedbelow.

1. Ascending: 0.5 5.00 0.05 50.05

0.05, 0.5, 5.00, 50.05

2. Descending: 12.6 1.92 21.62 13.56

21.62, 13.56, 12.6, 1.92

3. Ascending: 34.79 15.08 26.47 34.8

15.08, 26.47, 34.79, 34.8



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4. Descending: 14.36 14.63 41.33 13.99

41.33, 14.63, 14.36, 13.99

5. Ascending: 100.14 114.11 104.44 144.04

100.14, 104.44, 114.11, 144.04

6. Descending: 210.10 120.01 100.21 211.00

211.00, 210.10, 120.01, 100.21

L Fillinthenumbersthatare0.1moreand0.1lesserthanthegivennumbers.

Example: 5.9

1. 4.24 4.34 4.44 4. 10.0 10.1 10.2

2. 8.8 8.9 9.0 5. 10.98 11.08 11.18

3. 8.06 8.16 8.26 6. 7.1 7.2 7.3

M Foreachnumberpattern,writethecorrectdecimalinthebox.

1. 5.00 5.05 5.10 5.15 5.20

2. 12.22 12.12 12.02 11.92 11.82

3. 0.00 1.11 2.22 3.33 4.44

4. 6.95 6.8 6.65 6.5 6.35

5. 8.45 7.34 6.23 5.12 4.01



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N Writeadecimalandafractionthatrepresenttheshadedpartsineachdiagram.

Decimal Fraction

0.44—10

0.3737—–

100

2.3 2 3—10

1.48 1 48—–100

2.61 2 61—–100



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O Changeeachdecimalintofractioninthesimplestform.

1. 8.9 8 9—10 6. 1.12 1 3—

25

2. 0.42—5 7. 0.61

61—–100

3. 28.85 2817—20 8. 19.08 19 2—

25

4. 1.7 1 7—10 9. 22.55 2211—

20

5. 48.16 48 4—25 10. 200.02 200 1—

50

P Changeeachfractionintoadecimal.

1.6—

10 0.6 6.85—–

100 0.85

2. 1 91—–100 1.91 7. 2 2—

10 2.2

3. 8 7—–100 8.07 8. 93—

10 9.3

4. 267—–10 26.7 9. 252——

100 2.52

5. 1,250—–—100 12.50 10. 894——

100 8.94



59

Q Fill=or≠intheboxes.

1. 91—–100

≠ 0.11 6. 25.5 = 2,550—–—100

2. 4 3—10

= 4.3 7. 4.55 ≠ 455—–10

3. 6 60—–100

≠ 6.06 8. 14.71 ≠ 147—–100

4. 15 34—–100

= 15.34 9. 18.08 ≠ 18—–100

5. 809—–100

≠ 8.9 10. 44.44 = 4,444—–—100

R Matchthenumbersthatareequal.

1. 7—10 A 7 1—

2

2. 1 3—5 B 8.16

3. 7.5 C 0.7

4. 5.41 D 12 4—5

5. 3 3—4 E 1.60

6. 8 4—25 F 5 41—–

100

7. 4.02 G 3.75

8. 12.8 H 4 1—50



60

S Changeeachfractionintoadecimal.

1. 3—4

0.75 6. 2—5

0.4

2. 3—–50

0.06 7. 31—20

1.55

3. 11—–4

2.75 8. 61—20

3.05

4. 83—–50

1.66 9. 2 2—25

2.08

5. 2 3—5

2.6 10. 5—4

1.25

T Findtheanswers.

1. How many Baht are 25 Satang equal to?

Answer: 0.25 Baht

2. How many meters are 85 centimeters equal to?

Answer: 0.85 meter

3. How many kilograms are 9 kheed equal to?

Answer: 0.9 kilogram

4. How many centimeters are 75 millimeters equal to?

Answer: 7.5 centimeter

5. How many meters are 2 meters 50 centimeters equal to?

Answer: 2.5 meters

6. How many Baht are 275 Satang equal to?

Answer: 2.75 Baht

7. How many kheed are 1.3 kilograms equal to?

Answer: 13 kheed



61

U Findtheanswers.

1. Matt has 18.50 Baht. A box of milk costs 12.75 Baht. Does Matt have enough money to buy a box of milk?

Answer: Yes

2. Poy is 1.45 meters tall. Jin is 162 centimeters tall. Who is taller?

Answer: Jin is taller.

3. Mother buys 1 kilogram 5 kheed of oranges and 1.5 kilograms of mangoes. Which fruit weighs more?

Answer: Both fruits are equal in weight.

4. May has 225 centimeters of ribbon. Mint has 2 meters 50 centimeters of ribbon. Whose ribbon is longer?

Answer: Mint’s ribbon is longer.

5. Based on the table below, answer the questions. The table below shows the time recorded in a 50-meter freestyle

swimming competition.

Athlete Time(sec)

Ning 55.35

Nong 40.96

Nut 45.24

Nook 36.97

(a) Who is fastest? Nook

(b) Who is slowest? Ning

(c) Who is faster, Nong or Nut? Nong

(d) Who is the winner? Nook


Mathematics Pratomsuksa 5 Chapter 6 Mastery Practice

62

1.

What i s the decimal represented by the shaded parts in the diagram?A 1.0 C 0.6B 0.4 D 1.4

2.

What i s the decimal represented by the shaded parts in the diagram?A 0.6 C 1.5B 1.6 D 2.4

3. 1.03 is read asA one point zero threeB one zero threeC one point threeD one point three zero

4. 0.02 can be represented byA 2 squaresB 2 squares out of 10C 2 squares out of 100D zero squares

5. 732.62 is read asA seven hundred and thirty-

two point sixty-two

B seven hundred and thirty-two point six two

C seven hundred thirty-two and sixty-two

D seven hundred thirty-two and six two

6. What is the place value for the digit 3 in 14.23?A Tens B Ones C TenthsD Hundredths

7. What is the digit value for the digit 6 in 147.69?A 600 C 0.6B 60 D 0.06

8. Which number has the digit 7 with the value of 0.7?A 79.32 C 93.72B 97.32 D 93.27

9. 5 ones 6 hundredths is the same asA 506 C 5.6B 5.06 D 0.56

10. 103.24 is equivalent toA 100 + 30 + 0.2 + 0.4B 10 + 3 + 0.2 + 0.04C 100 + 30 + 0.2 + 0.04D 100 + 3 + 0.2 + 0.04

M a s t e er y P r a c t i cM a s t e er y P r a c t i c


Mathematics Pratomsuksa 5 Chapter 6 Mastery Practice

63

11. 3,000 + 900 + 50 + 0.06 =A 30,956B 3,950.6C 3,950.06D 3,950.60

12. Which of the following is true?A 0.7 = 0.70B 0.7 > 0.70C 0.70 < 0.7D 0.70 < 0.07

13. Which of the following is incorrect?A 42.37 > 42.07B 324.8 < 324.81C 321.04 < 321.4D 4.06 > 40.6

14. Which of the following sets of decimals is arranged in ascending order?A 0.91, 2.6, 4.02, 12.75B 12.75, 4.02, 2.6, 0.91C 0.91, 4.02, 2.6, 12.75D 0.91, 4.02, 12.75, 2.6

15. Which is more than 1?A 0.09 B 0.90 C 0.99D 9.99

16. 0.3 is equal to

A1—3 C

1—10

B3—1 D

3—10

17. Convert 1.04 into fraction.

A1—4 C

1—–104

B 12—5 D 1

4—–100

18. Which of the following is true?

A 0.02 = 1—20

B 0.2 = 1—2

C 0.25 = 1—4

D 0.5 = 1—5

19. How many meters are 347 centimeters equal to?A 347 metersB 34.7 metersC 3.47 metersD 0.347 meters

20. The table below shows the weights of four boys.

Boy Weight(kg)

Ake 29.42

Sak 28.00

Ahtit 27.59

Ace 30.01

Who is the lightest?A AkeB SakC AhtitD Ace


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06 Pri WB Math P5.pdf