NCERT Exemplar Solutions
Class 6 - Mathematics - Unit 3: IntegersProblems and Solutions
Class 6 - Mathematics - Unit 3: Integers
Question. 59
59. Match the items of Column I with that of Column II:
| Column I | Column II |
|---|---|
| (i) The additive inverse of +2 | (A) 0 |
| (ii) The greatest negative integer | (B) −2 |
| (iii) The greatest negative even integer | (C) 2 |
| (iv) The smallest integer greater than every negative integer | (D) 1 |
| (v) Sum of predecessor and successor of −1 | (E) −1 |
Answer:
(i) → (B) −2
(ii) → (E) −1
(iii) → (B) −2
(iv) → (A) 0
(v) → (B) −2
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Question. 60
60. Compute each of the following:
- \(30 + (-25) + (-10)\)
- \((-20) + (-5)\)
- \(70 + (-20) + (-30)\)
- \(-50 + (-60) + 50\)
- \(1 + (-2) + (-3) + (-4)\)
- \(0 + (-5) + (-2)\)
- \(0 - (-6) - (+6)\)
- \(0 - 2 - (-2)\)
Answer:
(a) −5, (b) −25, (c) 20, (d) −60, (e) −8, (f) −7, (g) 0, (h) 0
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Question. 61
61. Using integers with appropriate signs, write the following:
- 200 m above sea level
- 100 m below sea level
- 10 m above sea level
- Sea level
Answer:
(a) \(+200\), (b) \(-100\), (c) \(+10\), (d) \(0\)
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Question. 62
62. Write the opposite of each of the following:
- Decrease in size
- Failure
- Profit of Rs. 10
- 1000 A.D.
- Rise in water level
- 60 km south
- 10 m above the danger mark of river Ganga
- 20 m below the danger mark of the river Brahmaputra
- Winning by a margin of 2000 votes
- Depositing Rs.100 in the bank account
- 20°C rise in temperature
Answer:
(a) Increase in size, (b) Success, (c) Loss of Rs. 10, (d) 1000 B.C., (e) Fall in water level, (f) 60 km north, (g) 10 m below the danger mark, (h) 20 m above the danger mark, (i) Losing by a margin of 2000 votes, (j) Withdrawing Rs. 100 from the bank account, (k) 20°C fall in temperature
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Question. 63
63. Temperature at 12:00 noon was \(+5^{\circ}\text{C}\). It increased by \(3^{\circ}\text{C}\) in the first hour and decreased by \(1^{\circ}\text{C}\) in the second hour. What was the temperature at 2:00 pm?
Answer:
\(+7^{\circ}\text{C}\)
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Question. 64
64. Write the digits \(0,1,2,\ldots,9\) in this order and insert '+' or '−' between them to get the result 3.
Answer:
\(0+1+2+3-4+5+6+7-8-9=3\)
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Question. 65
Write the integer which is its own additive inverse.
Answer:
\(0\)
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Question. 66
Write six distinct integers whose sum is 7.
Answer:
\(-3,\,0,\,1,\,2,\,3,\,4\) (sum: \(-3+0+1+2+3+4=7\))
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Question. 67
Write the integer which is 4 more than its additive inverse.
Answer:
\(2\)
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Question. 68
Write the integer which is 2 less than its additive inverse.
Answer:
\(-1\)
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Question. 69
Write two integers whose sum is less than both the integers.
Answer:
\(-2\) and \(-3\): sum = \(-5\)
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Question. 70
Write two distinct integers whose sum is equal to one of the integers.
Answer:
\(0\) and \(5\): \(0+5=5\)
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Question. 71
71. Using number line, how do you compare
- two negative integers?
- two positive integers?
- one positive and one negative integer?
Answer:
(a) The negative integer nearer to 0 (smaller absolute value) is greater.
(b) The integer to the right is greater (larger value).
(c) Any positive integer is greater than any negative integer.
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Question. 72
72. Observe: \(1+2-3+4+5-6-7+8-9=-5\). Change one ‘−’ sign as ‘+’ sign to get the sum \(9\).
Answer:
Change “−7” to “+7”.
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Question. 73
Arrange in ascending order: \(-2, 1, 0, -3, +4, -5\).
Answer:
−5, −3, −2, 0, 1, 4
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Question. 74
Arrange in descending order: \(-3, 0, -1, -4, -3, -6\).
Answer:
0, −1, −3, −3, −4, −6
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Question. 75
Write two integers whose sum is 6 and difference is also 6.
Answer:
6 and 0
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Question. 76
Write five integers which are less than \(-100\) but greater than \(-150\).
Answer:
−101, −110, −120, −130, −149
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Question. 77
Write four pairs of integers which are at the same distance from 2 on the number line.
Answer:
(1, 3), (0, 4), (−1, 5), (−2, 6)
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Question. 78
The sum of two integers is 30. If one integer is \(-42\), find the other.
Answer:
72
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Question. 79
Sum of two integers is \(-80\). If one of the integers is \(-90\), find the other.
Answer:
10
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Question. 80
80. If we are at 8 on the number line, in which direction should we move to reach the integer
- \(-5\)
- \(11\)
- \(0\)
Answer:
(a) Left, (b) Right, (c) Left
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Question. 81
81. Using the number line, write the integer which is
- 4 more than \(-5\)
- 3 less than \(2\)
- 2 less than \(-2\)
Answer:
(a) \(-1\), (b) \(-1\), (c) \(-4\)
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Question. 82
82. Find the value of
\(49 - ( -40) - ( -3) + 69\).
Answer:
161
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Question. 83
83. Subtract \(-5308\) from the sum \([(-2100)+(-2001)]\).
Answer:
1207