 |
Maths Quiz for Class 8 Cubes and Cube Roots |
In this post, we are providing 20 online maths quiz
questions for class 8 cubes and cube roots. Online maths quiz will take around
20 minutes to complete it.
Question 1: The cube of which of the given numbers is odd?
A) 16
B) 18
C) 19
D) 22
Explanation: The cube of an even number is even and the cube of an odd number is odd. Since 19 is an odd number, the cube of 19 is odd.
Question 2: Which of the given numbers is a perfect cube?
A) 512
B) 324
C) 144
D) 225
Explanation: 512 = 8 × 8 × 8. Therefore, 512 is a perfect cube.
Question 3: Which of the following numbers is a perfect cube as well as a perfect square?
A) 729
B) 625
C) 576
D) 676
Explanation: 729 = 272
= 93. Therefore, 729 is a perfect cube as well as a perfect square.
Question 4: Which of the following numbers is not a perfect cube?
A) 125
B) 225
C) 216
D) 343
Explanation: 225 is not a perfect cube, because 225 = 15 × 15. It is a perfect square.
Question 5: If the ones digit of a number is 7, then find the ones digit of its cube.
A) 9
B) 3
C) 7
D) 1
Explanation: 7 × 7 × 7 = 49 × 7 = 343. Therefore, the ones digit is 3.
Question 6: Find the ones digit of the cube of 5792.
A) 2
B) 4
C) 8
D) 6
Explanation: The ones digit of 5792 is 2 and 2 × 2 × 2 = 8. Therefore, the ones digit of the cube of 5792 is 8.
Question 7: Find the cube of 12.
A) 729
B) 1728
C) 1331
D) 2744
Explanation: 123 = 12 × 12 × 12 = 1728
Question 8: The cube of -15 is __________.
A) -2744
B) 2744
C) 3375
D) -3375
Explanation: (-15)3 = -15 × -15 × -15 = -3375
Question 9: Express 53 as the sum of consecutive odd numbers.
A) 21 + 23 + 25 + 27 + 29
B) 19 + 21 + 23 + 25 + 27
C) 17 + 19 + 21 + 23 + 25
D) 15 + 17 + 18 + 21 + 23
Explanation: According to the properties of cube numbers, 53 = Sum of 5 odd numbers starting from 5 × (5 – 1) + 1, that is, 21 = 21 + 23 + 25 + 27 + 29
Question 10: How many odd numbers have to be added to get 113?
A) 9
B) 10
C) 11
D) 12
Explanation: To get 113, 11 odd numbers have to be added and the first odd number is 11 × (11 – 1) + 1, that is, 111.
Question 11: We know that a3
– (a – 1)3 = 1 + a × (a
– 1) × 3. Hence, find the value of 103 – 93.
A) 270
B) 271
C) 91
D) 272
Explanation: Since
a3 – (a – 1)3 = 1 + a × (a
– 1) × 3 => 103 – 93 = 1 + 10
× 9 × 3
= 271
Question 12: Which of the following decimals is a perfect cube?
A) 3.43
B) 0.343
C) 34.3
D) 0.0343
Explanation: 0.343 is a perfect cube, because 0.343 = 0.7 × 0.7 × 0.7
Question 13: Find the smallest number by which 2916 must be multiplied to obtain a perfect cube.
A) 2
B) 3
C) 4
D) 5
Explanation: 2916 = 3 × 3 × 3 × 3 × 3 × 3 × 2 × 2. To make it a perfect cube, we must multiply it by 2.
Question 14: Find the smallest number by which 875 must be divided to obtain a perfect cube.
A) 2
B) 3
C) 5
D) 7
Explanation: 875 = 5 × 5 × 5 × 7. To make it a perfect cube, we must divide it by 7.
Question 15: Find the cube root of 2197.
A) 11
B) 12
C) 13
D) 14
Explanation: 2197 = 13 × 13 × 13. Thus, the cube root of 2197 is 13.
Question 16: Find the cube root of 1.331.
A) 0.11
B) 1.1
C) 11
D) 1.2
Explanation: 1.331 = 1.1 × 1.1 × 1.1. Thus, the cube root of 1.331 is 1.1.
Question 17: The cube root of 3375 is _________.
A) 15
B) 12
C) 13
D) 25
Explanation: 3375 = 3 × 3 × 3 × 5 × 5 × 5 = 33 × 53. Thus, the cube root of 3375 is 3 × 5 = 15.
Question 18: Find the cube root of 64 × 343.
A) 24
B) 26
C) 28
D) 29
Explanation: 64 × 343 = 4 × 4 × 4 × 7 × 7 × 7 = 43 × 73. Thus, the cube root of 64 × 343 = 4 × 7 = 28
Question 19: The volume of a cube is 216 cu. cm. What the measure of each side of the cube?
A) 4 cm
B) 6 cm
C) 7 cm
D) 8 cm
Explanation: Each side of the cube = 3√216 = 3√6 × 6 × 6 = 6 cm
Question 20: Estimate the cube root of 21952.
A) 24
B) 26
C) 28
D) 38
Explanation: 21952 = 2 × 2 × 2 × 2 × 2 × 2 × 7 × 7 × 7 = 23 × 23 × 73. Thus, the cube root of 21952 = 2 × 2 × 7 = 28
Report Card
Total Questions Attempted: 0
Correct Answers: 0
Wrong Answers: 0
Percentage: 0%