# Grade 8 Cubes and Cube Roots Worksheets

## Grade 8 Maths Cubes and Cube Roots Multiple Choice Questions (MCQs)

1. Which of the following is not a perfect cube?
(a) 1
(b) 9
(c) 8
(d) 27

2. The value of 53 is ………………. .
(a) 125
(b) 15
(c) 10
(d) 75

3. The cube of an even number is always ………………… .
(a) odd number
(b) even number
(c) prime number
(d) none of these

4. The cube of an odd number is always ………………… .
(a) odd number
(b) even number
(c) prime number
(d) none of these

5. Each prime factor appears ………………. times in its cube?
(a) 2
(b) 3
(c) 1
(d) 4

6. Which of the following is Hardy-Ramanujan Number?
(a) 1724
(b) 1725
(c) 1727
(d) 1729

7. The smallest natural number by which 704 must be divided to obtain a perfect cube is
(a) 22
(b) 12
(c) 11
(d) 13

8. The expansion of a3 is …………………. .
(a) 3 × a
(b) a + a + a
(c) 3 × 3 × 3
(d) a × a × a

9. A cuboid has dimensions 5 cm, 2 cm, 5 cm. How many such cuboid will be needed to form a cube?
(a) 20
(b) 10
(c) 5
(d) 2

10. How many cuboids of dimensions 15 cm, 30 cm, 15 cm will be needed to form a cube?
(a) 15
(b) 4
(c) 30
(d) 5

11. The symbol for cube root is ……………… .
(a) $\sqrt{ }$
(b) $\sqrt{ }$
(c) $\sqrt{ }$
(d) None of these

12. The value of $\sqrt{343}$ is ……………….. .
(a) 8
(b) 7
(c) 6
(d) 3

13. If the volume of a cube is 125 cm3 then what would be the length of its side?
(a) 25
(b) 5
(c) 4
(d) 15

14. 9 is the cube root of ………………….. .
(a) 343
(b) 729
(c) 629
(d) 81

15. How many digits will be there in the cube root of 46656?
(a) 2
(b) 1
(c) 3
(d) 4

16. How many digits will I be there in the cube root of 512?
(a) 1
(b) 2
(c) 3
(d) 4

17. What will be the unit digit of $\sqrt{15625}$?
(a) 5
(b) 0
(c) 3
(d) 4

18. How many zeros will be there in the cube root of 27000?
(a) 3
(b) 0
(c) 1
(d) 2

19. If 83 = 512, then $\sqrt{512}$ = ………………… .
(a) 3
(b) 7
(c) 13
(d) 8

20. Find the cube root of 0.0027.
(a) 3
(b) 0.3
(c) 0.03
(d) None of these

### Class 8 Maths Cubes and Cube Roots Fill In The Blanks

1. There are ……………… perfect cubes between 1 and 1000.
2. Cube of a number ending 7 will end in the digit ……………… .
3. A perfect cube can be expressed as the product of ……………….. prime factors.
4. Sum of the cubes of first 3 natural numbers is equal to ………………. of their sum.
5. The least number by which 72 be multiplied to make it a perfect cube is ……………….. .

### Class 8 Maths Cubes and Cube Roots True(T) Or False(F)

1. There are five perfect cubes between 1 and 100.
2. For an integer a, a3 is always greater than a2.
3. Let x and y be natural number. If x divides y, then x3 divides y3.
4. $\sqrt{64+125}=\sqrt{64}+\sqrt{125}$
5. Cube roots of 1 are +1 and -1.

### Class 8 Maths Cubes and Cube Roots Very Short Answer Type Questions

1. Which is the smallest three-digit perfect cube?
2. Which is the greatest three-digit perfect cube?
3. By which smallest natural number 392 must be multiplied so as to make the product a perfect cube?
4. What will be the unit digit of the cube of a number ending with 2?
5. What will be the unit digit of the cube root of a number ends with 8?
6. What will be the unit digit of $\sqrt{216}$?

### Class 8 Maths Cubes and Cube Roots Short Answer Type Questions

1. If a3 – 1 = 1330, then a = ………………….
2. Find the cube root of $\frac{1331}{1728}$.
3. If $\sqrt{\frac{x}{y}}=\frac{2}{3}$ then $\frac{x}{y}$ =
4. Three numbers are in the ratio 1:2:3 and the sum of their cubes is 288. Find the numbers.

### Class 8 Maths Cubes and Cube Roots Long Answer Type Questions

1. Find the cube root of 13824 by prime factorisation method.
2. Parikshit makes a cuboid of plasticine of side 5 cm, 2 cm, 5 cm. Flow many such cuboids will be need to form a cube?
3. What will be the ten’s digit of the cube root of 91125?