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: 533 = 53 x 53 x 53
33 = 3x3x3 = 27
Hence, at the unit place, we will get 7.
Recheck: 533 = 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 = 26
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 = 33 × 32
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 = 33 × 3
Hence, we need to divide 81 by 3 to get:
81/3 = 27 = 33
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 = 23 × 113 × 5
Hence, we need to divide 53240 by 5
53240/5 = 10648 is a perfect cube.
8. The value of 43√1000 is:
A. 400
B. 40
C. 10
D. 4
Answer: B
Explanation: 43√1000 = 43√(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: 103 = 1000
203 = 8000
303 = 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. 2a3
B. 4a3
C. 8a3
D. 16a3
Answer: C. 8a3
Explanation:
(2a)3 = 2a x 2a x 2a
= (2 x 2 x 2) x (a x a x a)
= 8a3
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.
= 24 × 54 = 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 = 33 x 33
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 = 13 = 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