Chapter 2 – Fractions And Decimals

Class 7 Mathematics · 120 questions · 110 with answers

Solved examples

example-1Multiple choice

Savita is dividing 1 kg of sweets equally among her seven friends. How much does each friend receive? 3 1 1 3

  • (a)kg
  • (b)kg
  • (c)kg
  • (d)kg 4 4 2 28
Show solution

Solution: Correct answer is (b)

example-2Multiple choice

If of a number is 12, the number is

  • (a)9
  • (b)16
  • (c)18
  • (d)32
Show solution

Solution: Correct answer is (b) 2 5

example-3Multiple choice

Product of fractions and is 7 9 2×5 2+5 2×9 2×5

  • (a)
  • (b)
  • (c)
  • (d)7+9 2+9 5×7 7×9
Show solution

Solution: Correct answer is (d)

example-4Multiple choice

Given that 0 < p < q < r < s and p, q, r, s are integers, which of the following is the smallest? p +q p +s q +s r +s

  • (a)
  • (b)
  • (c)
  • (d)p + q r +s q +r p +r
Show solution

Solution: Correct answer is (a)

example-5Multiple choice

The next number of the pattern 60, 30, 15, _______ is 15 15

  • (a)10
  • (b)5
  • (c)
  • (d)4 2
Show solution

Solution: Correct answer is (d) 15-04-2018 UNIT 2

example-6Multiple choice

The decimal expression for 8 rupees 8 paise (in Rupees) is

  • (a)8.8
  • (b)8.08
  • (c)8.008
  • (d)88.0
Show solution

Solution: Correct answer is (b)

example-7Multiple choice

Each side of a regular hexagon is 3.5cm long. The perimeter of the given polygon is

  • (a)17.5cm
  • (b)21cm
  • (c)18.3cm
  • (d)20cm
Show solution

Solution: Correct answer is (b)

example-8Multiple choice

2.5 ÷ 1000 is equal to

  • (a)0.025
  • (b)0.0025
  • (c)0.2500
  • (d)25000
Show solution

Solution : Correct answer is (b)

example-9Multiple choice

Which of the following has the smallest value? 2 (0.2)2 2

  • (a)0.0002
  • (b)
  • (c)
  • (d)÷ 0.01 1000 2 100
Show solution

Solution: Correct answer is (a)

example-10Multiple choice

Which of the following has the largest value? 32 0.320 3.2 3.2

  • (a)
  • (b)
  • (c)
  • (d)0.05 50 0.05 50
Show solution

Solution: Correct answer is (a)

example-11Multiple choice

The largest of the following is 1 1

  • (a)0.0001
  • (b)
  • (c)(0.100)2
  • (d)÷ 0.1 1000 10
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Solution: Correct answer is (d) In Examples 12 to 19, fill in the blanks to make the statement true.

example-12Fill in the blanks

A fraction acts as an operator___________

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Solution: of FRACTIONS AND DECIMALS 29 15-04-2018 MATHEMATICS

example-13Fill in the blanks

Fraction which is reciprocal of is _________.

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Solution:

example-14Fill in the blanks

Product of a proper and improper fraction is ____________ the improper fraction.

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Solution: less than.

example-15Fill in the blanks

The two non-zero fractions whose product is 1, are called the ________ of each other.

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Solution: Reciprocal

example-16Fill in the blanks

5 rupees 5 paise = ` ________.

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Solution: 5.05

example-17Fill in the blanks

45mm = _________ m.

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Solution: 0.045

example-18Fill in the blanks

2.4 × 1000 = _________.

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Solution: 2400

example-19Fill in the blanks

To divide a decimal number by 100, we shift the decimal point in the number to the ________ by ______ places.

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Solution: left, two In Examples 20 to 23 state whether the statements are True or False.

example-20Short answer

Reciprocal of an improper fraction is an improper fraction.

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Solution: False 2 1

example-21Short answer

2 ÷2 = 2 5 5

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Solution:  2 1 12 5 12  False  because 2 ÷ 2 = × =  5 5 5 11 11  15-04-2018 UNIT 2

example-22Short answer

0.04 ÷ 0.2 = 0.2

Show solution

Solution: True

example-23Short answer

0.2 × 0.3 = 0.6

Show solution

Solution: False [as 0.2 × 0.3 = 0.06]

example-24Short answer

Find of 6 using circles with shaded parts. Fig. 2.1

Show solution

Solution: From the following figure, try to find out of 6. There are 12 shaded parts out of 18 parts which can be taken as shown below (Fig. 2.2), which means 4 wholes. Thus of 6 is 4. Fig. 2.2

example-25Short answer

Find the value of 1 1 1 + + 11 5   7 13 9

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Solution: Given expression = 1 1 1 + +  30   50  5        7   13  9 7 13 9 = + + 30 50 5 FRACTIONS AND DECIMALS 31 15-04-2018 MATHEMATICS 35 39 270 35 + 39 + 270 172 = + + = = 150 150 150 150 75

example-26Multiple choice

There is a 3 × 3 × 3 cube which consists of twenty seven 1 × 1 × 1 cubes (see Fig. 2.3). It is ‘tunneled’ by removing cubes from the coloured squares. Find:

  • (i)Fraction of number of small cubes removed to the number of small cubes left in given cube. Fig. 2.3
  • (ii)Fraction of the number of small cubes removed to the total number of small cubes.
  • (iii)What part is (ii) of (i)?
Show solution

Solution: (i) Number of small cubes removed = 1 + 1 + 1 + 1 + 1 +1 + 1=7 So, required fraction = (ii) Required fraction = 7 7 7 20 20 (iii) Required part is ÷ = × = 27 20 27 7 27

example-27Short answer

Ramu finishes part of a work in 1 hour. How much part of the work will be finished in 2 hours?

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Solution: The part of the work finished by Ramu in 1 hour = So, the part of the work finished by Ramu in 2 hours 1 1 11 1 11 × 1 11 = 2 × = × = = 5 3 5 3 5×3 15 11 1 Ramu will finish part of the work in 2 hours. 15 5 15-04-2018 UNIT 2

example-28Short answer

How many kg pieces can be cut from a cake of weight 4 kg?

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Solution: Observe the following figure representing 4 cakes each of 1 kg and try to give the answer. Fig. 2.4 In the above figure we look for ‘how many s are there in these 4 cakes?’ 2 3 That is, 4 ÷ =4× =6 3 2 Alternate Method This can be observed also in the following way. We get the answer as 6.

example-29Short answer

Harmeet purchased 3.5kg of potatoes at the rate of `13.75 per kg. How much money should she pay in nearest rupees?

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Solution: Cost of 1 kg of potatoes = ` 13.75. Cost of 3.5 kg of potatoes = ` 13.75 × 3.5 13.75 ×3.5 6875 4 1 2 5× 4 8.1 2 5 So, cost of 3.5 kg of potatoes = ` 48, to the nearest rupees. FRACTIONS AND DECIMALS 33 15-04-2018 MATHEMATICS

example-30Short answer

Kavita had a piece of rope of length 9.5 m. She needed some small pieces of rope of length 1.9 m each. How many pieces of the required length will she get out of this rope?

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Solution : The length of the rope = 9.5m The length of a small piece of rope = 1.9m Number of small pieces = 9.5 m ÷ 1.9m 9.5 9.5 × 10 = = 1.9 1.9 × 10 = =5 So, she will get 5 small pieces of rope.

example-31Short answer

Three boys earned a total of ` 235.50. What was the average amount earned per boy?

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Solution : Three boys earned = ` 235.50 235.50 The average amount earned per boy = ` The average amount earned per boy is ` 78.50.

example-32Multiple choice

Find the product of 1 5 1 7 4 5

  • (i)and
  • (ii)and
  • (iii)and 2 8 3 5 3 2 1 5 1× 5 5
Show solution

Solution : (i) × = = 2 8 2×8 16 1 7 1× 7 7 (ii) × = = 3 5 3×5 15 15-04-2018 UNIT 2 4 5 4×5 20 10 (iii) × = = = 3 2 3×2 6 3

example-33Multiple choice

Observe the 3 products given in Example 32 and now give the answers of the following questions.

  • (i)Does interchanging the fractions in the example, 1 5 × , affect the answer? 2 8
  • (ii)Is the value of the fraction in the product greater or less than the value of either fraction? 1 5 5 1
Show solution

Solution : (i) By interchanging × we get × 2 8 8 2 5 1 5 ×1 5 × = = which is same as the product we get 8 2 8×2 16 1 5 in Example 32 by multiplying and . This means 2 8 that interchanging the fractions does not affect the answer. (ii) By observing the 3 products given in the solution of Example 32, we come to know that the value of the fractions in the products are as follows (a) The product of two fractions whose value is less than 1 i.e. the proper fractions is less than each of the fractions that are multiplied. (b) The product of a proper and an improper fraction is less than the improper fractions and greater than the proper fraction. (c) The product of two improper fractions is greater than each of the two fractions.

example-34Short answer

Reshma uses m of cloth to stitch a shirt. How many shirts can she make with 2 m cloth?

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Solution : Study the following figures : Let represent m FRACTIONS AND DECIMALS 35 15-04-2018 MATHEMATICS Then, 9 fourths = =3 3 fourths 3 1 In fact, we calculate that “how many are in 2 ?” 4 4 And it is calculated as, 1 3 9 3 9 4 9× 4 9 2 ÷ = ÷ = × = = =3 4 4 4 4 4 3 4×3 3 Thus, 3 shirts can be made with 2 m of cloth. MATHEMATICS IN MUSIC

example-35Short answer

If the fraction of the frequencies of two notes have a common factor between the numerator and denominator, the two notes are harmonious. Use the graphic below to find the fraction of frequency of notes D and B. Frequency Chart Fig. 2.5 15-04-2018 UNIT 2

Show solution

Solution: Fraction of frequencies of notes D and B is Frequency of note D 297 3 × 3 × 3 ×11 = Frequency of note B = 495 = 3 × 3 × 5 ×11 So, the fraction of the frequencies of notes D and B is . Clearly, the notes D and B are harmonies. Find other pairs of notes which are harmonious. Application on Problem Solving Strategy

example-36Short answer

2 Khilona said that we have gone about 120km or of the way to the camp site. So, how much farther do we have to go?

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Solution : Understand and Explore the Problem • What do you know? • We know that 120km is about of the total distance. Plan a Strategy • Draw a diagram showing the distance that Khilona has already gone and the fractional part that it represents. Solve 2 1 • If of the distance is 120km, then of the distance 3 3 would be of 120km i.e. 60km. FRACTIONS AND DECIMALS 37 15-04-2018 MATHEMATICS The total distance is (120 + 60) km or 180km. Revise : Since of the total distance, denoted by x, equals 2x 120km, so the equation = 120 represents this problem. By solving we get x = 180 km. Thus the solution is checked. Think and Discuss 1. If of the total distance is 120 km, then how far is the camp site? 2. Apply both strategies i.e. by drawing and by using equation, to solve other problems and discuss with your friends that which method is easy.

Questions

Q2Short answer

1 1. × 5 is equal to:

Show answer

Correct answer 48, unattempated, wrong answer 1 134. 60 sec or 1 min 135. 23 rd January 136. 19,759 m Puzzle 1 (i) (ii) –1 –9 4 7 –2 –6 –1 3 –2 –7 –4 –3 1 4 –8 5 –3 0 –2 –3 3 –5 5 6 –8 Puzzle 2 (i) –10 (iv) –3 (ii) 8 (v) –33 (iii) 7 (vi) 18 Increasing order –33 < –10 < –3 < 7 < 8 < 18 E U C L I D Puzzle 3 Solution: September OSKNRKPNOV Puzzel 4 (a) Puzzel 5 (a) 6 (b) –2 (c) –8 Puzzel 6 Arrange –12 in the centre and –2, 4, –5, 50, –25, 20 in clockwise order. 1. (b) 2. (c)

Q5Multiple choice

5 26 52 2

  • (a)
  • (b)
  • (c)
  • (d)6 25 25 5 3 3 2. 3 ÷ is equal to: 4 4 (a) 3 (b) 4 (c) 5 (d) 1 3 3. A ribbon of length 5 m is cut into small pieces each of length m. 4 4 Number of pieces will be: (a) 5 (b) 6 (c) 7 (d) 8 15-04-2018 UNIT 2 2 6 13 4. The ascending arrangement of , , is: 3 7 21
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(d) 6 25 25 5 3 3 2. 3 ÷ is equal to: 4 4 (a) 3 (b) 4 (c) 5 (d) 1 3 3. A ribbon of length 5 m is cut into small pieces each of length m. 4 4 Number of pieces will be: (a) 5 (b) 6 (c) 7 (d) 8 15-04-2018 UNIT 2 2 6 13 4. The ascending arrangement of , , is: 3 7 21

Q6Multiple choice

2 13 13 2 6 6 13 2 2 6 13

  • (a), ,
  • (b), ,
  • (c), ,
  • (d), ,
Show answer

(a) , ,

Q7Multiple choice

3 21 21 3 7 7 21 3 3 7 21 5. Reciprocal of the fraction is: 2 3

  • (a)2
  • (b)3
  • (c)
  • (d)3 2 6. The product of and 4 is: 5 3 3 5 (a) 3 (b) 5 (c) 13 (d) 13 13 13 5 3 7. The product of 3 and 4 is: 2 24 1 1 (a) 17 (b) (c) 13 (d) 5 5 5 5 13
Show answer

(c)

Q8Multiple choice

Pictorial representation of 3 × is:

  • (a)
  • (b)
  • (c)
  • (d)1 4
Show answer

(b)

Q9Multiple choice

÷ equal to: 5 5 4 1 5 1

  • (a)
  • (b)
  • (c)
  • (d)5 5 4 4
Show answer

(d) 5 5 4 4

Q10Multiple choice

The product of 0.03 × 0.9 is:

  • (a)2.7
  • (b)0.27
  • (c)0.027
  • (d)0.0027
Show answer

(c) 0.027

Q11Multiple choice

÷ 6 is equal to: 30 5 30 6

  • (a)
  • (b)
  • (c)
  • (d)7 42 42 7 FRACTIONS AND DECIMALS 39 15-04-2018 MATHEMATICS 1 9
Show answer

(b)

Q12Multiple choice

5 ÷ is equal to 6 2 31 1 1 31

  • (a)
  • (b)
  • (c)5
  • (d)6 27 27 27 1 1
Show answer

(d) 6 27 27 27 1 1

Q13Multiple choice

Which of the following represents of ? 3 6 1 1 1 1 1 1 1 1

  • (a)+
  • (b)–
  • (c)×
  • (d)÷ 3 6 3 6 3 6 3 6 3 2
Show answer

(c) ×

Q14Multiple choice

of is equal to 7 5 5 5 1 6

  • (a)
  • (b)
  • (c)
  • (d)12 35 35 35 1 2
Show answer

(d) 12 35 35 35 1 2

Q15Multiple choice

One packet of biscuits requires 2 cups of flour and 1 cups of 2 3 sugar. Estimated total quantity of both ingredients used in 10 such packets of biscuits will be

  • (a)less than 30 cups
  • (b)between 30 cups and 40 cups
  • (c)between 40 cups and 50 cups
  • (d)above 50 cups Vocabulary • Equivalent Fraction 1. A number that consists of a whole number and a fraction is called a/an ___________? • Fraction 2. An____________________ is a number that • Improper represents a part of a whole. Fraction 3. A fraction whose numerical (abrolute) value • Mixed Number is greater than 1 is called a/an ______________, • Proper and a fraction whose numerical value is Fraction between 0 and 1 is called a/an _____________ 4. _____________ mean the same value. 15-04-2018 UNIT 2
Show answer

(c) between 40 cups and 50 cups

Q16Multiple choice

The product of 7 and 6 is 1 1 3 3

  • (a)42
  • (b)47
  • (c)42
  • (d)47 4 4 4 4
Show answer

(b) 47

Q17Multiple choice

On dividing 7 by , the result is 14 35 14 35

  • (a)
  • (b)
  • (c)
  • (d)2 4 5 2
Show answer

(d) 2 4 5 2

Q18Multiple choice

2 ÷ 5 is equal to 8 40 40 8

  • (a)
  • (b)
  • (c)
  • (d)15 3 5 3 4 1
Show answer

(a)

Q19Multiple choice

of 5 kg apples were used on Monday. The next day of what was 5 3 left was used. Weight (in kg) of apples left now is 2 1 2 4

  • (a)
  • (b)
  • (c)
  • (d)7 14 3 21
Show answer

(c)

Q20Multiple choice

The picture interprets 1 1 3 1

  • (a)÷3
  • (b)3×
  • (c)×3
  • (d)3 ÷ 4 4 4 4 In Questions 21 to 44, fill in the blanks to make the statements true. 2 4
Show answer

(b) 3×

Q21Fill in the blanks

Rani ate part of a cake while her brother Ravi ate of the 7 5 remaining. Part of the cake left is __________

Q22Fill in the blanks

The reciprocal of is ___________

Q23Fill in the blanks

of 27 is ___________ FRACTIONS AND DECIMALS 41 15-04-2018 MATHEMATICS

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18

Q24Fill in the blanks

of 45 is ______

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36 7 3 76 1 15 2 17 8 1

Q25Fill in the blanks

4 × 6 is equal to _______ 1 2

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or 25

Q26Fill in the blanks

of 4 is _______ 2 7 1 6

Q27Fill in the blanks

of is ______ 9 5 Think and Discuss 1. Explain whether you need to find a common denominator to compare 2 1 and − . 3 2 2. Describe the steps you would use to compare 0.235 and 0.239. 3 7

Q28Fill in the blanks

The lowest form of the product 2 × is ________ 7 9

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or 1

Q29Fill in the blanks

÷ 4 is equal to _______

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3 3 7 15 9 9 5

Q30Fill in the blanks

of 25 is ________ 1 5 1 6

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10

Q31Fill in the blanks

÷ = _____ 5 6 5 5

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X

Q32Fill in the blanks

3.2 × 10 = _______

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32

Q33Fill in the blanks

25.4 × 1000 = _______

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25400

Q34Fill in the blanks

93.5 × 100 = _______

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9350

Q35Fill in the blanks

4.7 ÷ 10 = ______

Show answer

0.47

Q36Fill in the blanks

4.7 ÷ 100 = _____

Show answer

0.047

Q37Fill in the blanks

4.7 ÷ 1000 = ______

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0.0047

Q38Fill in the blanks

The product of two proper fractions is _______ than each of the fractions that are multiplied.

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Less

Q39Fill in the blanks

While dividing a fraction by another fraction, we _________ the first fraction by the _______ of the other fraction.

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multiply, reciprocal

Q40Fill in the blanks

8.4 ÷ ______ = 2.1 15-04-2018 UNIT 2

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4

Q41Fill in the blanks

52.7 ÷ _______ = 0.527

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100

Q42Fill in the blanks

0.5 _____ 0.7 = 0.35 5 10

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X

Q43Fill in the blanks

2 ____ = 3 3

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X

Q44Fill in the blanks

2.001 ÷ 0.003 = __________ In each of the Questions 45 to 54, state whether the statement is True or False.

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667

Q45Short answer

The reciprocal of a proper fraction is a proper fraction.

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False

Q46Short answer

The reciprocal of an improper fraction is an improper fraction. Product of their denominators

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False

Q47Short answer

Product of two fractions = Product of their numerators

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False

Q48Short answer

The product of two improper fractions is less than both the fractions.

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False

Q49Short answer

A reciprocal of a fraction is obtained by inverting it upside down.

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True

Q50Short answer

To multiply a decimal number by 1000, we move the decimal point in the number to the right by three places.

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True

Q51Short answer

To divide a decimal number by 100, we move the decimal point in the number to the left by two places.

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True

Q52Short answer

1 is the only number which is its own reciprocal. 2 2

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True

Q53Short answer

of 8 is same as ÷ 8. 3 3 4 4

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False

Q54Short answer

The reciprocal of is . 7 7

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False

Q55Short answer

If 5 is added to both the numerator and the denominator of the fraction , will the value of the fraction be changed? If so, will the value increase or decrease?

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Yes, increase

Q56Short answer

What happens to the value of a fraction if the denominator of the fraction is decreased while numerator is kept unchanged?

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The value of fraction would increase

Q57Short answer

Which letter comes of the way among A and J? FRACTIONS AND DECIMALS 43 15-04-2018 MATHEMATICS

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D

Q58Short answer

If of a number is 10, then what is 1.75 times of that number?

Show answer

26.25

Q59Short answer

In a class of 40 students, of the total number of students like to eat rice only, of the total number of students like to eat chapati only and the remaining students like to eat both. What fraction of the total number of students like to eat both?

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5 5

Q60Short answer

Renu completed part of her home work in 2 hours. How much part of her home work had she completed in 1 hours?

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part

Q61Short answer

Reemu read th pages of a book. If she reads further 40 pages, she would have read th pages of the book. How many pages are left to be read?

Show answer

24 pages

Q62Short answer

Write the number in the box such that 3 15 × = 7 98 1 2

Q63Short answer

Will the quotient 7 ÷ 3 be a fraction greater than 1.5 or less 6 3 than 1.5? Explain.

Show answer

Greater than 1.5 12 14

Q64Short answer

Describe two methods to compare and 0.82. Which do you think is easier and why? Think and Discuss 1. Give an example of an addition problem that involves connecting an improper fraction in the final step. 7 7 14 2. Explain why + does not equal . 9 9 18 15-04-2018 UNIT 2

Show answer

convert both into (1) decimals (2) fractions 16 2 1

Q65Multiple choice

Health: The directions for a pain reliever recommend that an adult of 60 kg and over take 4 tablets every 4 hours as needed, and an adult who weighs between 40 and 50 kg take only 2 tablets every 4 hours as needed. Each tablet weighs gram.

  • (a)If a 72 kg adult takes 4 tablets, how many grams of pain reliever is he or she receivings?
  • (b)How many grams of pain reliever is the recommended dose for an adult weighing 46 kg?
Show answer

(a) If a 72 kg adult takes 4 tablets, how many grams of pain reliever is he or she receivings?

(b) How many grams of pain reliever is the recommended dose for an adult weighing 46 kg?

Q66Multiple choice

Animals: The label on a bottle of pet vitamins lists dosage guidelines. What dosage would you give to each of these animals?

  • (a)a 18 kg adult dog
  • (b)a 6 kg cat
  • (c)a 18 kg pregnant dog Do Good Pet Vitamins • Adult dogs: tsp (tea spoon full) per 9kg body weight • Puppies, pregnant dogs, or nursing dogs: tsp per 4.5kg body weight • Cats: tsp per 1kg body weight
Show answer

(a) a 18 kg adult dog

(b) a 6 kg cat

(c) a 18 kg pregnant dog Do Good Pet Vitamins • Adult dogs: tsp (tea spoon full) per 9kg body weight • Puppies, pregnant dogs, or nursing dogs: tsp per 4.5kg body weight • Cats: tsp per 1kg body weight

Q67Short answer

How many kg boxes of chocolates can be made with 1 kg chocolates?

Show answer

24 boxes

Q68Short answer

Anvi is making bookmarker like the one shown in Fig. 2.6. How many bookmarker can she make from a 15 m long ribbon? Fig. 2.6 FRACTIONS AND DECIMALS 45 15-04-2018 MATHEMATICS

This question refers to a figure in the original PDF.

Show answer

142 book marker

Q69Multiple choice

A rule for finding the approximate length of diagonal of a square is to multiply the length of a side of the square by 1.414. Find the length of the diagonal when :

  • (a)The length of a side of the square is 8.3 cm.
  • (b)The length of a side of the square is exactly 7.875 cm.
Show answer

(a) The length of a side of the square is 8.3 cm.

(b) The length of a side of the square is exactly 7.875 cm.

Q70Multiple choice

The largest square that can be drawn in a circle has a side whose length is 0.707 times the diameter of the circle. By this rule, find the length of the side of such a square when the diameter of the circle is

  • (a)14.35 cm
  • (b)8.63 cm
Show answer

(a) 14.35 cm

(b) 8.63 cm

Q71Multiple choice

To find the distance around a circular disc, multiply the diameter of the disc by 3.14. What is the distance around the disc when :

  • (a)the diameter is 18.7 cm?
  • (b)the radius is 6.45 cm?
Show answer

(a) the diameter is 18.7 cm?

(b) the radius is 6.45 cm?

Q72Short answer

What is the cost of 27.5 m of cloth at ` 53.50 per metre?

Show answer

1471.25

Q73Multiple choice

In a hurdle race, Nidhi is over hurdle B and of the way through the race, as shown in Fig. 2.7. Fig. 2.7 Then, answer the following: 4

This question refers to a figure in the original PDF.

  • (a)Where will Nidhi be, when she is of the way through the race?
  • (b)Where will Nidhi be when she is of the way through the race?
  • (c)Give two fractions to tell what part of the race Nidhi has finished when she is over hurdle C.
Q74Short answer

Diameter of Earth is 12756000m. In 1996, a new planet was discovered whose diameter is of the diameter of Earth. Find the diameter of this planet in km.

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741.6 km (approximetly)

Q75Short answer

What is the product of and its reciprocal? 15-04-2018 UNIT 2 1 1 + 2

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1 6 2 27 18

Q76Short answer

Simplify: 2 5 1 1 2 ÷ 2 5 1 1 +

Q77Short answer

Simplify: 4 5 3 3 1− × 8 5 3 1 3

Q78Short answer

Divide by  of  10 4 5 1 2 1

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2

Q79Short answer

of a number equals ÷ . What is the number? 8 5 20

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64

Q80Short answer

Heena’s father paid an electric bill of ` 385.70 out of a 500 rupee note. How much change should he have received?

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114.30

Q81Short answer

The normal body temperature is 98.6°F. When Savitri was ill her temperature rose to 103.1°F. How many degrees above normal was that? Think and Discuss 1. Name the number of decimal places in the product of 5.625 and 2.75. 2. Give an example of two fractions whose product is an integer due to common factors.

Show answer

4.50F 125 31

Q82Multiple choice

Meteorology: One measure of average global temperature shows how each year varies from a base measure. The table shows results for several years. Year 1958 1964 1965 1978 2002 Difference from Base 0.10°C – 0.17°C – 0.10°C  1  0.54°C   C  50  See the table and answer the following:

  • (a)Order the five years from coldest to warmest.
  • (b)In 1946, the average temperature varied by – 0.030C from the base measure. Between which two years should 1946 fall when the years are ordered from coldest to warmest? FRACTIONS AND DECIMALS 47 15-04-2018 MATHEMATICS Science Application
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(a) Order the five years from coldest to warmest.

(b) In 1946, the average temperature varied by – 0.030C from the base measure. Between which two years should 1946 fall when the years are ordered from coldest to warmest? FRACTIONS AND DECIMALS 47 15-04-2018 MATHEMATICS Science Application

Q83Multiple choice

In her science class, Jyoti learned that the atomic weight of Helium is 4.0030; of Hydrogen is 1.0080; and of Oxygen is 16.0000. Find the difference between the atomic weights of:

  • (a)Oxygen and Hydrogen
  • (b)Oxygen and Helium
  • (c)Helium and Hydrogen
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(a) Oxygen and Hydrogen

(b) Oxygen and Helium

(c) Helium and Hydrogen

Q84Short answer

Measurement made in science lab must be as accurate as possible. Ravi measured the length of an iron rod and said it was 19.34 cm long; Kamal said 19.25 cm; and Tabish said 19.27 cm. The correct length was 19.33 cm. How much of error was made by each of the boys?

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Ravi + 0.01 cm, Kamal –0.08 cm, Tabish – 0.06 cm

Q85Short answer

When 0.02964 is divided by 0.004, what will be the quotient?

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7.41

Q86Short answer

What number divided by 520 gives the same quotient as 85 divided by 0.625?

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70720

Q87Short answer

A floor is 4.5 m long and 3.6 m wide. A 6 cm square tile costs ` 23.25. What will be the cost to cover the floor with these tiles?

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104625

Q88Short answer

Sunita and Rehana want to make dresses for their dolls. Sunita has 3 1 m of cloth, and she gave of it to Rehana. How much did Rehana 4 3 have?

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m

Q89Short answer

A flower garden is 22.50 m long. Sheela wants to make a border along one side using bricks that are 0.25 m long. How many bricks will be needed?

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90 bricks

Q90Short answer

How much cloth will be used in making 6 shirts, if each required 1 1 2 m of cloth, allowing m for waste in cutting and finishing in 4 8 each shirt?

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14 m

Q91Short answer

A picture hall has seats for 820 persons. At a recent film show, one 3 2 usher guessed it was full, another that it was full. The ticket 4 3 office reported 648 sales. Which usher (first or second) made the better guess?

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first usher

Q92Short answer

For the celebrating children’s students of Class VII bought sweets for ` 740.25 and cold drink for ` 70. If 35 students contributed equally what amount was contributed by each student?

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23.15

Q93Short answer

The time taken by Rohan in five different races to run a distance of 500 m was 3.20 minutes, 3.37 minutes, 3.29 minutes, 3.17 minutes and 3.32 minutes. Find the average time taken by him in the races. 15-04-2018 UNIT 2

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3.27 minutes

Q94Short answer

A public sewer line is being installed along 80 m of road. The supervisor says that the labourers will be able to complete 7.5 m in one day. How long will the project take to complete?

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11 days

Q95Short answer

The weight of an object on moon is its weight on Earth. If an object weighs 5 kg on Earth, how much would it weigh on the moon?

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0.93 kg

Q96Multiple choice

In a survey, 200 students were asked what influenced them most to buy their latest CD. The results are shown in the circle graph.

  • (a)How many students said radio influenced them most?
  • (b)How many more students were influenced by radio than by a music video channel?
  • (c)How many said a friend or relative influenced them or they heard the CD in a shop? FRACTIONS AND DECIMALS 49 15-04-2018 MATHEMATICS
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(a) How many students said radio influenced them most?

(b) How many more students were influenced by radio than by a music video channel?

(c) How many said a friend or relative influenced them or they heard the CD in a shop? FRACTIONS AND DECIMALS 49 15-04-2018 MATHEMATICS

Q97Short answer

In the morning, a milkman filled 5 L of milk in his can. He sold to 3 7 Renu, Kamla and Renuka L each; to Shadma he sold L; and to 4 8 Jassi he gave 1 L. How much milk is left in the can?

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L 1 5

Q98Short answer

Anuradha can do a piece of work in 6 hours. What part of the work can she do in 1 hour, in 5 hours, in 6 hours?

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part of work, part of work, complete work 6 6 1 23 7

Q99Short answer

What portion of a ‘saree’ can Rehana paint in 1 hour if it requires 5 3 1 hours to paint the whole saree? In 4 hours? In 3 hours? 5 2

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, ,

Q100Short answer

Rama has 6 kg of cotton wool for making pillows. If one pillow takes 1 kg, how many pillows can she make?

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5 pillows 5 25 10

Q101Short answer

It takes 2 m of cloth to make a shirt. How many shirts can Radhika make from a piece of cloth 9 m long?

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4 shirts

Q102Short answer

Ravi can walk 3 km in one hour. How long will it take him to walk to his office which is 10 km from his home?

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3 hours

Q103Short answer

Raj travels 360 km on three fifths of his petrol tank. How far would he travel at the same rate with a full tank of petrol?

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600 km

Q104Short answer

Kajol has ` 75. This is of the amount she earned. How much did she earn? Think and Discuss 1. Explain how you can be sure that a fraction is simplified. 2. Give the sign of a fraction in which the numerator is negative and the denominator is negative. 15-04-2018 UNIT 2

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200 5 10

Q105Multiple choice

It takes 17 full specific type of trees to make one tonne of paper. If there are 221 such trees in a forest, then (i) what fraction of forest will be used to make;

  • (a)5 tonnes of paper.
  • (b)10 tonnes of paper. (ii) To save part of the forest how much of paper we have to save.
Q106Short answer

Simplify and write the result in decimal form :  2  1  2 1 ÷  + 1 ÷ 3  + 1 ÷ 2   9  5  3

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5.1875 13 13

Q107Multiple choice

Some pictures

  • (a)to (f) are given below. Tell which of them show: 1 3 1 (1) 2 × (2) 2 × (3) 2 × 4 7 3 1 2 1 (4) ×4 (5) 3 × (6) ×3 4 9 4 (a)
  • (b)
  • (c)
  • (d)(e) (f) FRACTIONS AND DECIMALS 51 15-04-2018 MATHEMATICS
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(d) (e) (f) FRACTIONS AND DECIMALS 51 15-04-2018 MATHEMATICS

(c)

(b)

(a) to (f) are given below. Tell which of them show: 1 3 1 (1) 2 × (2) 2 × (3) 2 × 4 7 3 1 2 1 (4) ×4 (5) 3 × (6) ×3 4 9 4 (a)

Q108Short answer

Evaluate : (0.3) × (0.3) – (0.2) × (0.2) 0.6 0.16

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0.05

Q109Short answer

Evaluate + 0.3 0.4 (0.2 × 0.14) + (0.5 × 0.91)

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2.4

Q110Short answer

Find the value of : (0.1 × 0.2)

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24.15

Q111Short answer

A square and an equilateral triangle have a side in common. If side of triangle is cm long, find the perimeter of figure formed (Fig. 2.8). Fig. 2.8

This question refers to a figure in the original PDF.

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cm or 6 cm

Q112Short answer

Rita has bought a carpet of size 4 m × 6 m. But her room size is 1 1 3 m × 5 m. What fraction of area should be cut off to fit wall to 3 3 wall carpet into the room? 2 2

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3 3 3

Q113Short answer

Family photograph has length 14 cm and breadth 10 cm. It has 5 5 border of uniform width 2 cm. Find the area of framed photograph. 3 1

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305 cm2

Q114Short answer

Cost of a burger is ` 20 and of Macpuff is ` 15 . Find the cost of 4 2 4 burgers and 14 macpuffs. 1 1

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300

Q115Short answer

A hill, 101 m in height, has th of its height under water. What is 3 4 the height of the hill visible above the water?

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76 m

Q116Short answer

Sports: Reaction time measures how quickly a runner reacts to the starter pistol. In the 100 m dash at the 2004 Olympic Games, Lauryn Williams had a reaction time of 0.214 second. Her total race time, including reaction time, was 11.03 seconds. How long did it take her to run the actual distance? 15-04-2018 UNIT 2

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10.816 2 1 1 1 1 2 1

Q117Short answer

State whether the answer is greater than 1 or less than 1. Put a ‘ü’ mark in appropriate box. Questions Greater than 1 Less than 1 2 1 ÷ 3 2 2 2 ÷ 3 1 6÷ 1 1 ÷ 5 2 1 1 4 ÷3 3 2 2 1 ×8 3 2

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Greater than 1: ÷ , 6 ÷ , 4 ÷3 , ×8 3 2 4 3 2 3 2 OSKNRKPNOV 2 2 1 1 Less than 1: ÷ , ÷ 3 1 5 2 7 3

Q118Short answer

There are four containers that are arranged in the ascending order of their heights. If the height of the smallest container given in the figure is expressed as x = 10.5 cm. Find the height of the largest container. In Questions 119 to 122, replace ‘?’ with appropriate fraction.

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37.5

Q119Short answer

120. FRACTIONS AND DECIMALS 53 15-04-2018 MATHEMATICS

Q121Short answer

122. What is the Error in each of question 123 to 125? 1 1

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500

Q123Short answer

A student compared – and –0.3. He changed – to the decimal 4 4 –0.25 and wrote, “Since 0.3 is greater than 0.25, –0.3 is greater than –0.25”. What was the student’s error?

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Error –0.30 > –0.25

Q124Short answer

A student multiplied two mixed fractions in the following manner: 4 1 1 2 × 3 = 6 . What error the student has done? 7 4 7 1 1 1

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mixed fractions are not converted into improper fraction.

Q125Multiple choice

In the pattern + + + ..... which fraction makes the sum greater 3 4 5 than 1 (first time)? Explain. (D) Applications Game 1: Shade

  • (i)of the circles in box (a)
  • (ii)of the triangles in box (b)
  • (iii)of the squares in box (c) 15-04-2018
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