Cubes and Cube Roots Class 8 MCQ Maths Chapter 7

MCQ on Cubes and Cube Roots for Class 8

Class 8 Maths Chapter 7 Cubes and Cube Roots MCQ

MCQ of Cubes and Cube Roots Class 8

I. Choose the correct answer.

Question 1.
Which of the following is Hardy-Ramanujan number ?
A) 1792
B) 1927
C) 1729
D) 1972
(OR)
Ramanujan number _________
A) 1792
B) 1279
C) 1972
D) 1792
Answer:
C) 1729 & A) 1792

Question 2.
What are two ways of expressing Ramanujan number ?
p) 1³ + 2³
q) 9³ + 10³
r) 11³ + 8³
s) 7³ + 12³
A) p, q
B) q, r
C) r, s t
D) p, s
Answer:
A) p, q

Question 3.
Pick the odd number
A) 9
B) 27
C) 125
D) 64
Answer:
A) 9

Question 4.
5³ can be expressed as sum of 5 consecutive odd numbers starting from ________
A) 23
B) 25
C) 27
D) 21
Answer:
D) 21

Question 5.
k³ can be expressed as sum of ‘k’ con-secutive odd numbers starting from _________
A) k(k – 1)
B) k(k – 1) + 1
C) k(k + 1)
D) k(k + 1) (k + 2)
Answer:
B) k(k – 1) + 1

Question 6.
Sum of 10 consecutive odd numbers starting from ___________ equals to 10³.
A) 90
B) 91
C) 93
D) 95
Answer:
B) 91

Question 7.
Value of k³ – l³ where (k = l + 1), is equal to _________ .
A) 1 + (k × l) × 3
B) 3 + (k × l)
C) 1 – 3(kl)
D) 3 + (k . l) × 5
Answer:
A) 1 + (k × l) × 3

Question 8.
12³ – 11³ = __________ .
A) 336
B) 396
C) 397
D) 387
Answer:
C) 397

Question 9.
How many perfect cubes (cube numbers) are below 100 ?
A) 8
B) 64
C) 16
D) 4
Answer:
D) 4

Question 10.
A number ‘p’ is factorised as 8 × 4 × 9 × 3, then what least number can make it perfect cube by multiplication ?
A) 3
B) 8
C) 2
D) 9
Answer:
C) 2

Question 11.
×××× P is a perfect cube. Then possible values for ‘P’ is __________ .
A) 0 to 9
B) 2 to 8
C) 3 to 7
D) 4 to 6
Answer:
A) 0 to 9

Question 12.
Cube of a number ending with 7 ends with __________ .
A) 7
B) 6
C) 5
D) 3
Answer:
D) 3

Question 13.
A perfect cube ending with’P’whose cubic root also ending with ‘P’. So, the value of ‘P’ is ________ .
A) 6
B) 9
C) A (or) B
D) none
Answer:
C) A (or) B

Question 14.
A perfect cube ending with 2. Then its cubic root ends with __________ .
A) 2
B) 8
C) 6
D) 4
Answer:
B) 8

Question 15.
Cubic root of a number ends with 4, then the number ends with __________ .
A) 2
B) 1
C) 4
D) none
Answer:
C) 4

Question 16.
If ‘pq’ is a perfect cube, then __________ also a perfect cube.
A) pq0
B) pq00
C) pq000
D) pq0000
Answer:
C) pq000

Question 17.
Which of the following will not be a perfect cube ?
A) 64000
B) 125000000
C) 9000
D) 27000
Answer:
C) 9000

Question 18.
What makes 160 a perfect cube ?
A) By adding 4
B) Multiplying by 400
C) Dividing by 20
D) All the above
Answer:
D) All the above

Question 19.
\(\sqrt[3]{17576}\) = __________ .
A) 16
B) 26
C) 36
D) 46
Answer:
B) 26

Question 20.
Which of the following statements are true ?
p : Cube of any odd number is odd.
q : There is no perfect cube ends with 8.
r : Cube of a number ending with 4 ends with 4.
s : If a number have 4 zeros at ending, then it wont be a perfect cube.
A) p, q
B) p, s
C) p, r, s
D) none
Answer:
C) p, r, s

Question 21.
What is the cube root of 4⁵ × 3⁶ × 2²?
A) 48
B) 144
C) 576
D) 1728
Answer:
B) 144

Question 22.
Cube root of 64 is __________
A) 4
B) 6
C) 8
D) 10
Answer:
A) 4

Question 23.
Which of the following statements is FALSE ?
A) The cube of any odd number is an odd number.
B) The cube of a number can end with any digit.
C) The cube of a single-digit number may be a single-digit number.
D) The cube of an even number may be an odd number.
Answer:
D) The cube of an even number may be an odd number.

II. Fill in the blanks.

1. A number, that is equal to its cube root = __________ .
Answer:
-1, 1

2. Cube root of = \(\frac{-343}{729}\) __________ .
Answer:
\(\frac{-7}{9}\)

3. A perfect cube ending with 6, its cube root ends with __________ .
Answer:
6

4. \(\sqrt[3]{64000}\) – \(\sqrt[3]{27000}\) + \(\sqrt[3]{8}\) + \(\sqrt[3]{-1}\) = __________ .
Answer:
11

5. By what number should be divide 270 to get a perfect cube __________ .
Answer:
10

6. \(\sqrt{100}\) – \(\sqrt[3]{1000}\) – √x = 0 ⇒ x = __________ .
Answer:
400

7. 2 × 5 × 2 × 10 × x is a perfect cube, then x = __________ .
Answer:
5

8. (2190 + P) is a perfect cube, then ‘P’ = __________ .
Answer:
7

9. Smallest perfect cube in Natural numbers is __________ .
Answer:
1

10. \(\frac{4 \times 8 \times 12}{t}\) is a perfect cube, then ‘t’ = __________ .
Answer:
6

11. Number of perfect cubes below 1000 = __________ .
Answer:
9

12. Number of perfect cubes in between 800 and 2000 = __________ .
Answer:
3

13. \(\sqrt[3]{1728}\) – \(\sqrt[3]{1331}\) + \(\sqrt[3]{729}\) + \(\sqrt[3]{P}\) = 13, then P = __________ .
Answer:
27

14. Cube root of 8000 is __________ .
Answer:
20

III. Match the following.

Question 1.

A	B
1) 123	a) 9
2) \(\sqrt[3]{729}\) =	b) 1331
3) (a000) is the lowest 4-digit perfect cube then a = _________	c) 5
4) \(\sqrt[3]{x \times \times \times 5}\) = ×× P, then ‘P’ = _________	d) 1728
5) \(\sqrt{121}-\sqrt[3]{z}\) = 0, then z = _________	e) 1

Answer:
(1, d) (2, a) (3, e) (4, c) (5, b)

A	B
1) 123	d) 1728
2) \(\sqrt[3]{729}\) =	a) 9
3) (a000) is the lowest 4-digit perfect cube then a = _________	e) 1
4) \(\sqrt[3]{x \times \times \times 5}\) = ×× P, then ‘P’ = _________	c) 5
5) \(\sqrt{121}-\sqrt[3]{z}\) = 0, then z = _________	b) 1331

Question 2.

A	B
1) (\(\frac{6 \times 9 \times 5}{P}\)) is a perfect cube, p = _________	a) 729
2) Perfect cube next to 1000 is = _________	b) 63
3) 73 – 63 = _________	c) 1 + (7 × 6 × 3)
4) 31 + 33 + 35 + 37 + 39 + 41 = _________	d) 1331
5) Highest 3 digit perfect square number = _________	e) 10

Answer:
(1, e) (2, d) (3, c) (4, b) (5, a)

A	B
1) (\(\frac{6 \times 9 \times 5}{P}\)) is a perfect cube, p = _________	e) 10
2) Perfect cube next to 1000 is = _________	d) 1331
3) 73 – 63 = _________	c) 1 + (7 × 6 × 3)
4) 31 + 33 + 35 + 37 + 39 + 41 = _________	b) 63
5) Highest 3 digit perfect square number = _________	a) 729

Class 8 Maths MCQ