chapter 1: integers exercise – 1

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Home » R.D. Sharma Solutions » R.D. Sharma Class 7 Solutions » Chapter 1 Integers » Integers Exercise 1.1 Question: 1 Determine each of the following products: (i) 12 × 7 (ii) (-15) × 8 (iii) (- 25) × (- 9) (iv) (125) × (- 8) Solution: (i) We have, 12 × 7 = 84 [The product of two integers of like signs is equal to the product of their absolute value] (ii) We have, (- 15) × 8 [The product of two integers of opposite = (- 15 × 8) signs is equal to the additive inverse of the = –120 [product of their absolute values] (iii) We have, (-25) × (-9) = + (25 × 9) = 225 (iv) We have, (125) × (- 8) = - (125 × 8) = –1000 Question: 2 Find each of the following products: (i) 3 × (- 8) × 5 (ii) 9 × (- 3) × (- 6) (iii) (- 2) × 36 × (- 5) (iv) (- 2) × (- 4) × (- 6) × (- 8) Solution: (i) We have, 3 × (- 8) × 5 = – (3 × 8) × 5 = (- 24) × 5 = – (24 × 5) = – 120 (ii) We have, 9 × (-3) × (- 6) Complete JEE Main/Advanced Course and Test Series OFFERED PRICE: Rs. 15,900 View Details Xpress Buy 731 Video Lectures Revision Notes Test paper with Video Solution Mind Map Study Planner NCERT Solutions Discussion Forum Previous Year Papers Submit or Course Features Register and Get connected with our counsellors. Name Email Select Grade Related Resources Integers Exercise 1.3 Chapter 1: Integers Exercise – 1.1 +91 Connect Leave a message

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Page 1: Chapter 1: Integers Exercise – 1

Home » R.D. Sharma Solutions » R.D. Sharma Class 7 Solutions » Chapter 1 Integers » Integers Exercise 1.1

Question: 1Determine each of the following products:

(i) 12 × 7

(ii) (-15) × 8

(iii) (- 25) × (- 9)

(iv) (125) × (- 8)

Solution:(i) We have,

12 × 7 = 84 [The product of two integers of like signs is equal to the product of their absolutevalue]

(ii) We have,

(- 15) × 8 [The product of two integers of opposite

= (- 15 × 8) signs is equal to the additive inverse of the

= –120 [product of their absolute values]

(iii) We have,

(-25) × (-9)

= + (25 × 9)

= 225

(iv) We have,

(125) × (- 8)

= - (125 × 8)

= –1000

Question: 2Find each of the following products:

(i) 3 × (- 8) × 5

(ii) 9 × (- 3) × (- 6)

(iii) (- 2) × 36 × (- 5)

(iv) (- 2) × (- 4) × (- 6) × (- 8)

Solution:(i) We have,

3 × (- 8) × 5

= – (3 × 8) × 5

= (- 24) × 5

= – (24 × 5)

= – 120

(ii) We have,

9 × (-3) × (- 6)

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Page 2: Chapter 1: Integers Exercise – 1

= - (9 × 3) × (- 6)

= (- 27) × (- 6)

= + (27 × 6)

= 162

(iii) We have,

(-2) × 36 × (- 5)

= - (2 × 36) × (- 5)

= (- 72) × (- 5)

= (72 × 5)

= 360

(iv) We have,

(- 2) × (- 4) × (- 6) × (- 8)

= (2 × 4) × (6 × 8)

= (8 × 48)

= 384

Question: 3Find the value of:

(i) 1487 × 327 + (- 487) × 327

(ii) 28945 × 99 - (- 28945)

Solution:(i) We have,

1487 × 327 + (- 487) × 327

= 486249 – 159249

= 327000

(ii) We have,

28945 × 99 - (- 28945)

= 2865555 – 28945

= 2894500

Question: 4Complete the following multiplication table:

Second Number

X - 4 -3 - 2 -1 0 1 2 3 4

- 4

FirstNumber

- 2

-1

0

1

2

3

4

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Page 3: Chapter 1: Integers Exercise – 1

Is the multiplication table symmetrical about the diagonal joining the upper left corner tothe lower right corner?

Solution:Second number

X - 4 - 3 - 2 - 1 0 1 2 3 4

- 4 16 12 8 4 0 -4 -8 -12 -16

First number12 9 6 3 0 -3 -6 -9 -12

-3

-2 8 6 4 2 0 -2 -4 -6 -8

-1 4 3 2 1 0 -1 -2 -3 -4

0 0 0 0 0 0 0 0 0 0

1 -4 -3 -2 -1 0 1 2 3 4

2 -8 -6 -4 -2 0 2 4 6 8

3 -12 -9 -6 -3 0 3 6 9 12

4 -16 -12 -8 -4 0 4 8 12 16

Question: 5Determine the integer whose product with ‘-1’ is

(i) 58

(ii) 0

(iii) – 225

Solution:(i) 58 x (–1) = – (58 x 1)

= – 58

(ii) 0 x (–1) = 0

(iii) (–225) x (–1) = + (225 x 1)

= 225

Question: 6What will be the sign of the product if we multiply together

(i) 8 negative integers and 1 positive integer?

(ii) 21 negative integers and 3 positive integers?

(iii) 199 negative integers and 10 positive integers?

Solution:(i) Positive ∵ [- ve × - ve = + ve]

(ii) Negative ∵ [- ve × + ve = - ve]

(iii) Negative

Question: 7State which is greater:

(i) (8 + 9) × 10 and 8 + 9 × 10

(ii) (8 - 9) × 10 and 8 – 9 × 10

(iii) ((-2) - 5) × - 6 and (-2) - 5 × (- 6)

Solution:(i) (8 + 9) × 10 = 17 × 10

Page 4: Chapter 1: Integers Exercise – 1

= 170

8 + 9 × 10 = 8 + 90 = 98

(8 + 9) × 10 > 8 + 9 × 10

(ii) (8 - 9) × 10 = - 1 × 10

= - 10

8 – 9 × 10 = 8 – 90 = - 82

(8 - 9) × 10 > 8 – 9 × 10

(iii) ((-2) – 5) × – 6 = (- 7) × (- 6)

= (7 x 6)

= 42

(– 2) – 5 x (– 6) = – 2 + (5 x 6)

= 30 – 2

= 28

Therefore, ((-2) – 5×(- 6)) > (- 2) – 5 × (- 6)

Question: 8(i) If a× (-1) = - 30, is the integer a positive or negative?

(ii) If a × (-1) = 30, is the integer a positive or negative?

Solution:(i) When multiplied by ‘a’ negative integer, a gives a negative integer. Hence, ‘a’ should be

a positive integer.

a = 30

(ii) When multiplied by ‘a’ negative integer, a gives a positive integer. Hence, ‘a’ should be

a negative integer.

a = – 30

Question: 9 Verify the following:

(i) 19 × (7 + (-3)) = 19 × 7 + 19 × (-3)

(ii) (-23)[(-5)+ (+19)] = (-23) × (- 5) + (- 23) × (+19)

Solution:(i) L.H.S = 19 × (7+ (-3))

= 19 × (7-3)

= 19 × 4

= 76

R.H.S = 19 × 7 + 19 × (-3)

= 133 – 57

= 76

Therefore, L.H.S = R.H.S

(ii) L.H.S = (-23)[(-5) + (+19)]

= (-23)[-5 + 19]

= (-23)[14]

= – 322

R.H.S = (-23) × (-5) + (-23) × (+19)

= 115 – 437

Page 5: Chapter 1: Integers Exercise – 1

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= –322

Therefore, L.H.S = R.H.S

Question: 10Which of the following statements are true?

(i) The product of a positive and a negative integer is negative.

(ii) The product of three negative integers is a negative integer.

(iii) Of the two integers, if one is negative, then their product must be positive.

(iv) For all non-zero integers a and b, a × b is always greater than

either a or b.

(v) The product of a negative and a positive integer may be zero.

(vi) There does not exist an integer b such that for a >1, a × b = b × a = b. <

Solution:(i) True

(ii) True

(iii) False

(iv) False

(v) False

(vi) True

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Page 6: Chapter 1: Integers Exercise – 1

Home » R.D. Sharma Solutions » R.D. Sharma Class 7 Solutions » Chapter 1 Integers » Integers Exercise 1.2

Question: 1Divide:

(i) 102 by 17

(ii) –85 by 5

(iii) –161 by –23

(iv) 76 by –19

(v) 17654 by –17654

(vi) (–729) by (–27)

(vii) 21590 by – 10

(viii) 0 by –135

Solution:(i) We have,

(ii) We have,

(iii) We have,

(iv) We have,

(v) We have,

(vi) We have,

(vii) We have,

(viii) We have,

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Integers Exercise 1.3

Chapter 1: Integers Exercise – 1.2

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Page 7: Chapter 1: Integers Exercise – 1

Question: 2 Fill in the blanks:

(i) 296 ÷ …. = - 148

(ii) – 88 ÷ …. = 11

(iii) 84 ÷ …. = 12

(v) …. ÷ 156 = - 2

(vi) …. ÷ 567 = - 1

Solution:(i) We have,

(ii) We have,

(iii) 84/12 = 7

(iv) …. ÷ -5 = 25

25 × (- 5) = - 125

(v) …. ÷ 156 = - 2

- (156 × 2)

= – 312

(vi) x/567 = - 1

⇒ x = - (567 × 1)

= – 567

∴ - (567/567) = -1

Question: 3Which of the following statements are true?

(i) 0 ÷ 4 = 0

(ii) 0 ÷ (-7) = 0

(iii) -15 ÷ 0 = 0

(iv) 0 ÷ 0 = 0

(v) (- 8) ÷ (- 1) = - 8

(vi) – 8 ÷ (- 2) = 4<

Solution:(i) True

(ii) True

(iii) False

(iv) False

(v) False

(vi) True

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Page 8: Chapter 1: Integers Exercise – 1

Home » R.D. Sharma Solutions » R.D. Sharma Class 7 Solutions » Chapter 1 Integers » Integers Exercise 1.3

Question: 1Find the value of 36 ÷ 6 + 3.

Solution:36 ÷ 6 + 3 = 6 + 3

= 9

Question: 2Find the value of 24 + 15 ÷ 3.

Solution:24 + 15 ÷ 3 = 24 + 5

= 29

Question: 3Find the value of 120 – 20 ÷ 4.

Solution:120 – 20 ÷ 4 = 120 - 5

= 115

Question: 4Find the value of 32 - (3 × 5) + 4.

Solution:32 – (3 x 5) + 4 = 32 – 15 + 4

= 17 + 4

= 21

Question: 5Find the value of 3 - (5 – 6 ÷ 3).

Solution:3 - (5 – 6 ÷ 3) = 3 - (5 - 2)

= 3 – 3

= 0

Question: 6Find the value of 21 – 12 ÷ 3 × 2.

Solution:

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Page 9: Chapter 1: Integers Exercise – 1

21 – 12 ÷ 3 × 2 = 21 – 123 × 2

= 21 – 4 × 2

= 21 – 8

= 13

Question: 7Find the value of 16 + 8 ÷ 4 – 2 × 3.

Solution:16 + 8 ÷ 4 – 2 × 3

= 16 + 2 – 6

= 18 – 6

= 12

∴ 16 + 8 ÷ 4 – 2 × 3 = 12

Question: 8Find the value of 28 – 5 × 6 + 2.

Solution:28 – 5 × 6 + 2 = 28 - (5 × 6) + 2

= 28 – 30 + 2

= 30 – 30

= 0

Question: 9Find the value of (-20) × (-1) + (-28) ÷ 7.

Solution:(-20) × (-1) + (-28) ÷ 7 = 20 + ∣-28∣ ∣7∣

= 20 - 287

= 20 – 4

= 16

Question: 10Find the value of (-2) + (-8) ÷ (- 4).

Solution:(-2) + (-8) ÷ (- 4) = - 2 + ∣- 8∣ ∣- 4∣

= – 2 + 2

= 0

Question: 11Find the value of (- 15) + 4 ÷ (5 - 3).

Solution:-15 + 4 ÷ (5 - 3) = - 15 + 4 ÷ 2

= – 15 + 2

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Page 10: Chapter 1: Integers Exercise – 1

� 728 VideoLectures

� Revision Notes � Previous YearPapers

� Mind Map� Study Planner

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� Test paper withVideo Solution

CompleteAIPMT/AIIMSCourse and TestSeries

OFFERED PRICE: Rs.15,900

View DetailsXpress Buy

Course Features

= – 13

-15 + 4 ÷ (5 - 3) = - 13

Question: 12Find the value of (- 40) × (-1) + (-28) ÷ 7.

Solution:(- 40) × (-1) + (-28) ÷ 7 = 40 + (- 4)

= 40 – 4

= 36

Question: 13Find the value of (-3) + (-8) ÷ (-4) - 2× (-2).

Solution:(-3) + (-8) ÷ (-4) – 2 × (-2) = (-3) + (-8)(-4) - 2×(-2)

= – 3 + 2 + 4

= 6 – 3

= 3

Question: 14Find the value of (-3) × (-4) ÷ (-2) + (-1).

Solution:(-3) × (-4) ÷ (-2) + (-1) = 12 ÷ (-2) + (-1)

= – 6 – 1

= – 7

∴ (-3) × (-4) ÷ (-2) + (-1) = - 7

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