# Class 8 Maths Chapter 7 Cubes and Cube Roots MCQs

**Class 8 Maths Chapter 7 Cubes and Cube Roots MCQs** (Questions and Answers) are available online for students. These multiple-choice questions are designed by experts, according to the CBSE syllabus (2021-2022) and NCERT guidelines. The chapter-wise objective questions are given at BYJU’S to make each student learn each concept and lead them to score better marks in exams. Also, learn important questions for class 8 Maths here.

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## MCQs on Class 8 Cubes and Cube Roots

Multiple choice questions (MCQs) are given for Class 8 Cubes and Cube Roots chapter. Each problem has four multiple options, in which one is the right answer. Students have to solve each problem and choose the correct answer.

**1. The one’s digit of the cube of 53 is:**

A. 9

B. 3

C. 7

D. 1

Answer: **C**

Explanation: 53^{3} = 53 x 53 x 53

3^{3} = 3x3x3 = 27

Hence, at the unit place, we will get 7.

Recheck: 53^{3} = 53 x 53 x 53 = 148877

**2. The prime factorisation of 64 is**:

A. 2 x 2 x 2

B. 4 x 4 x 4

C. 8 x 8 x 8

D. None of the above

**Answer: D**

Explanation: 64 = 2 x 2 × 2 x 2 x 2 x 2 = 2^{6}

**3. Which of the following is not a perfect cube?**

A. 216

B. 1000

C. 243

D. 1331

Answer: **C**

Explanation: 243 = 3 × 3 × 3 × 3 × 3 = 3^{3} × 3^{2}

**4. By what number should 81 be divided to get a perfect cube?**

A. 3

B. 6

C. 7

D. 9

Answer: **A**

Explanation: The prime factorisation of 81 will be:

81 = 3 × 3 × 3 × 3

81 = 3^{3} × 3

Hence, we need to divide 81 by 3 to get:

81/3 = 27 = 3^{3}

**5. By what number should we divide 135 to get a perfect cube?**

A. 3

B. 5

C. 7

D. 9

Answer:** B**

Explanation: 135 = 3 x 3 x 3 x 5

We can see, 5 is the extra number which cannot be paired in a group of 3.

Hence, 135/5 = 27

**6. Cube root of 512 is:**

A. 4

B. 6

C. 8

D. 12

Answer: **C**

Explanation: By prime factorisation, we get:

512 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2

^{3}√512 = 2 × 2 × 2 = 8

**7. What should be divided by 53240 to make it a perfect cube?**

A. 5

B. 10

C. 15

D. 20

Answer: **A**

Explanation: The prime factorisation of 53240

53240 = 2 × 2 × 2 × 11 × 11 × 11 × 5 = 2^{3} × 11^{3} × 5

Hence, we need to divide 53240 by 5

53240/5 = 10648 is a perfect cube.

**8. The value of 4 ^{3}√1000 is:**

A. 400

B. 40

C. 10

D. 4

Answer: **B**

Explanation: 4^{3}√1000 = 4^{3}√(10×10×10) = 4 × 10 = 40

**9. A perfect cube of a number having 0 at its unit place, ends with _____ zeros.**

A. 1

B. 2

C. 3

D. 4

Answer: **C**

Examples: 10^{3} = 1000

20^{3} = 8000

30^{3} = 27000

**10. Cube root of 15625 is:**

A. 5

B. 15

C. 25

D. 35

Answer: **C**

Explanation: 15625 = 5 x 5 x 5 x 5 x 5 x 5

^{3}√15625 = 5 × 5 = 25

**11. Which of the following is a perfect cube?**

A.125

B. 36

C. 75

D. 100

Answer: A. 125

Explanation:

125 = 5 × 5 × 5 = 5³

**12. What is the cube of 2a?**

A. 2a^{3}

B. 4a^{3}

C. 8a^{3}

D. 16a^{3}

Answer: C. 8a^{3}

Explanation:

(2a)^{3} = 2a x 2a x 2a

= (2 x 2 x 2) x (a x a x a)

= 8a^{3}

**13. 1. The cube root of 13824 is __________.**

A. 36

B. 25

C. 24

D. 16

Answer: C. 24

Explanation: Prime factorisation of 13824 is:

13824=2×2×2×2×2×2×2×2×2×3×3×3

13824=(2×2×2)×(2×2×2)×(2×2×2)×(3×3×3)

Taking cube root both the sides, we get;

(13824)⅓ = 2 x 2 x 2 x 3 = 24

**14. Which of these numbers is not a cube number?**

A. 10000

B. 343

C. 64

D. 729

Answer: A. 10000

Explanation: By prime factorisation method.

10000 = 2 × 2 × 2 × 2 × 5 × 5 × 5 × 5.

= 2^{4} × 5^{4} = 2³ × 2 × 5³ × 5

Thus, the factors cannot be cubed.

**15. When the square of a number is subtracted from the cube of the same number, it becomes 100. Find the number.**

A.1

B. 2

C. 4

D. 5

Answer: D. 5

Explanation: Square of 5 = 5 x 5 = 25

Cube of 5 = 5 x5x5 = 125

125 – 25 = 100

**16. Which is the smallest natural number by which 243 must be multiplied to make the product a perfect cube?**

A. 3

B. 9

C. 8

D. 7

Answer: A. 3

Explanation: 243 x 3 = 729

Hence, by prime factorisation of 729 we get;

729 = 3 x 3 x 3 x 3 x 3 x 3

729 = 3^{3} x 3^{3}

Taking cube root on both the sides, we get;

(729)⅓ = 3 x 3 = 9

**17. The one’s digit of the cube of the number 111 is:**

A. 1

B. 2

C. 3

D. 9

Answer: A. 1

Explanation: The unit place of 111 has 1.

Cube of 1 = 1^{3} = 1 x 1 x 1 = 1

**18. The cube of 23 is:**

A. 2304

B. 12167

C. 529

D. 23

Answer: B. 12167

Explanation: Cube of 23 = 23 x 23 x 23 = 12167

**19. The one’s digit of the cube of the number 242 is**

A. 2

B. 4

C. 6

D. 8

Answer: D. 8

Explanation: The unit digit of 242 is 2.

Cube of 2 = 2 x 2 x 2 = 8

**20. Find the smallest number by which the number 200 must be multiplied to obtain a perfect cube.**

A. 2

B. 10

C. 5

D. 100

Answer: C. 5

Explanation: The prime factorisation of 200 gives:

200 = 2 × 2 × 2 × 5 × 5 = 2³ × 5 × 5

Now multiply by 5 on both sides.

200 x 5 = 2³ × 53

(1000)1/3 = 2 × 5 = 10