NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 1: Number SystemFill in the Blanks
Class 7 - Mathematics - Unit 1: Number System
Question. 31
(–a) + b = b + Additive inverse of ________.
Answer:
(–a) + b = b + Additive inverse of a.
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Question. 33
(–157) × (–19) + 157 = ________
Answer:
(–157) × (–19) + 157 = 3140
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Question. 34
[(–8) + ______ ] + ______ = ______ + [(–3) + ______ ] = –3
Answer:
[(–8) + 5] + 0 = –3 + [(–3) + 0] = –3
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Question. 35
On the following number line, (–4) × 3 is represented by the point ________.

Answer:
On the number line, (–4) × 3 is represented by the point D.
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Question. 36
If x, y and z are integers then (x+ ___ ) + z = ___ + (y + ___ )
Answer:
(x+ y) + z = x + (y + z)
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Question. 38
(–8) + (–8) + (–8) = _____ × (–8)
Answer:
(–8) + (–8) + (–8) = 3 × (–8)
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Question. 39
11 × (–5) = – ( ____ × ____ ) = ____
Answer:
11 × (–5) = – (11 × 5) = –55
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Question. 41
(–23) × (42) = (–42) × ____
Answer:
(–23) × (42) = (–42) × 23
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Question. 42
While multiplying a positive integer and a negative integer, we multiply them as ______ numbers and put a ______ sign before the product.
Answer:
While multiplying a positive integer and a negative integer, we multiply them as whole numbers and put a negative sign before the product.
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Question. 43
If we multiply ______ number of negative integers, then the resulting integer is positive.
Answer:
If we multiply even number of negative integers, then the resulting integer is positive.
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Question. 44
If we multiply six negative integers and six positive integers, then the resulting integer is ______.
Answer:
If we multiply six negative integers and six positive integers, then the resulting integer is positive.
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Question. 45
If we multiply five positive integers and one negative integer, then the resulting integer is ______.
Answer:
If we multiply five positive integers and one negative integer, then the resulting integer is negative.
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Question. 46
______ is the multiplicative identity for integers.
Answer:
1 is the multiplicative identity for integers.
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Question. 47
We get additive inverse of an integer a when we multiply it by ______.
Answer:
We get additive inverse of an integer a when we multiply it by (–1).
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Question. 49
(–5) × (–6) × (–7) = ______
Answer:
(–5) × (–6) × (–7) = –210
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Question. 51
[12 × (–7)] × 5 = ______ × [(–7) × ______ ]
Answer:
[12 × (–7)] × 5 = 12 × [(–7) × 5]
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Question. 52
23 × (–99) = ______ × (–100 + ______ ) = 23 × ______ + 23 × ______
Answer:
23 × (–99) = 23 × (–100 + 1) = 23 × –100 + 23 × 1