NCERT Solutions for Class 8 Chapter 7 Cubes and Cube Roots -Free PDF Download
Free PDF download of NCERT Solutions Maths Class 8 Solutions Chapter 7 – Cubes and Cube Roots solved by Expert Maths Teachers on CoolGyan.Org. All Chapter 7 – Cubes and Cube Roots Questions with Solutions for NCERT to help you to revise complete Syllabus and Score More marks.
Maths Revision Notes for Class 8
| Chapter Name | Cubes and Cube Roots |
| Chapter | Chapter 7 |
| Exercise | Exercise 7.2 |
| Class | Class 8 |
| Subject | Maths NCERT Solutions |
| Board | CBSE |
| TEXTBOOK | CBSE NCERT |
| Category | NCERT Solutions |
NCERT SOLVED
1. Find the cube root of each of the following numbers by prime factorization method:
(i) 64
(ii) 512
(iii) 10648
(iv) 27000
(v) 15625
(vi) 13824
(vii) 110592
(viii) 46656
(ix) 175616
(x) 91125
Ans. (i) 64
= 
= 4
(ii) 512
= 
= 8
(iii) 10648
= 
= 22
(iv) 27000
= 
= 30
(v) 15625
= 
= 25
(vi) 13824
= 
= 24
(vii) 110592
= 
= 48
(viii) 46656
= 
= 36
(ix) 175616
= 
= 56
(x) 91125
= 
= 45
2. State true or false:
(i) Cube of any odd number is even.
(ii) A perfect cube does not end with two zeroes.
(iii) If square of a number ends with 5, then its cube ends with 25.
(iv) There is no perfect cube which ends with 8.
(v) The cube of a two digit number may be a three digit number.
(vi) The cube of a two digit number may have seven or more digits.
(vii) The cube of a single digit number may be a single digit number.
Ans. (i) False
Since, 
are all odd.
(ii) True
Since, a perfect cube ends with three zeroes.
e.g. 
so on
(iii) False
Since,
(Did not end with 25)
(iv) False
Since 
= 1728
[Ends with 8]
And 
= 10648
[Ends with 8]
(v) False Since 
= 1000
[Four digit number]
And 
= 1331
[Four digit number]
(vi) False Since 
= 970299
[Six digit number]
(vii) True
= 1
[Single digit number]
= 8
[Single digit number]
3. You are told that 1,331 is a perfect cube. Can you guess without factorization what is its cube root? Similarly guess the cube roots of 4913, 12167, 32768.
Ans. We know that = 1000 and Possible cube of = 1331
Since, cube of unit’s digit = 1
Therefore, cube root of 1331 is 11.
4913
We know that 
= 343
Next number comes with 7 as unit place 
= 4913
Hence, cube root of 4913 is 17.
12167
We know that 
= 27
Here in cube, ones digit is 7
Now next number with 3 as ones digit
= 2197
And next number with 3 as ones digit
= 12167
Hence cube root of 12167 is 23.
32768
We know that = 8
Here in cube, ones digit is 8
Now next number with 2 as ones digit
= 1728
And next number with 2 as ones digit
= 10648
And next number with 2 as ones digit
= 32768
Hence cube root of 32768 is 32.
