Q71Written answer
If a2 ends in 9, then a3 ends in 7.
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Worked solution
Solution:-
False.
Let a2 be 72
So, 72 = 49
Then, 73 = 343
NCERT Exemplar · Class 8 · Maths
Chapter 3: Squares and Square Roots & Cubes and Cube Roots
Practice each question, then open the answer or worked solution.
Questions
142 questionsQ72Written answer
The square root of a perfect square of n digits will have (n + 1)/2 digits, if n is odd.
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Worked solution
Solution:-
True.
Let au assume the perfect square has 9 digits, then its square root has 5 digits
i.e. (9 + 1)/2 = 10/2 = 5
Q73Written answer
Square root of a number x is denoted by √x.
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Worked solution
Solution:-
True.
Q74Written answer
A number having 7 at its ones place will have 3 at the units place of its square.
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Worked solution
Solution:-
False.
Let us take the number having 7 at its ones place i.e.47 and
Its square 472 = 2209
Q75Written answer
A number having 7 at its ones place will have 3 at the ones place of its cube.
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Worked solution
Solution:-
True.
Let us take the number having 7 at its ones place i.e. 37 and
Its square 373 = 50,653
Another number is 273 = 19,683
Q76Written answer
The cube of a one digit number cannot be a two digit number.
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Worked solution
Solution:-
False.
The cube of 3 .i.e. 43 = 4 × 4 × 4 = 64
Q77Written answer
Cube of an even number is odd.
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Worked solution
Solution:-
False.
The cube of an even number is always an even number.
23 = 8
43 = 64
Q78Written answer
Cube of an odd number is even.
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Worked solution
Solution:-
False.
The cube of odd number is always an odd number.
33 = 27
53 = 125
Q79Written answer
Cube of an even number is even.
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Worked solution
Solution:-
True.
The cube of an even number is always an even number.
83 = 512
123 = 1728
Q80Written answer
Cube of an odd number is odd.
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Worked solution
Solution:-
True.
The cube of odd number is always an odd number.
73 = 343