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8th Grade > Mathematics

EXPONENTS AND POWERS MCQs

Total Questions : 58 | Page 2 of 6 pages
Question 11. Simplify :(162133)÷152
  1.    (35)2
  2.    (925)2
  3.    (53)2
  4.    (259)2
 Discuss Question
Answer: Option A. -> (35)2
:
A
We know that for anon-zero integer a and any integer m,
am=1am.
62=162
162=62=36
Similarly, 133=33=27 and 152=52=25.
(162133)÷152=(3627)÷25
=925
=3252
=(35)2(ambm=(ab)m
Question 12. ((2)2)2× (33 ÷42) ÷ 32 is equal to 
  1.    3
  2.    1
  3.    123
  4.    27
 Discuss Question
Answer: Option A. -> 3
:
A
((2)2)2× (33 ÷42) ÷ 32
=42 ×2716× 19((am)n=amn)
= 16 × 2716× 19
=279
= 3
Question 13. 8,780,000,000,000= _______.
  1.    8.78×1012
  2.    8.78×10−12
  3.    87.8×1012
  4.    87.8×10−11
 Discuss Question
Answer: Option A. -> 8.78×1012
:
A
8,780,000,000,000=878×1010
=8.78×102×1010
=8.78×1012
=87.8×101×1012
=87.8×1011
(Using am×an=am+n)
Question 14. 1 micron  equals  to _________. 
  1.    110000
  2.    106  m    
  3.    10−6  m    
  4.    10−5 m    
 Discuss Question
Answer: Option C. -> 10−6  m    
:
C
1 micron = 106m.
Question 15. The value of  27 is _____.
  1.    128
  2.    64
  3.    256
  4.    512
 Discuss Question
Answer: Option A. -> 128
:
A
27 is 2 multiplied by itself, 7 times.
So, 27=2×2×2×2×2×2×2=128
Question 16. Find the multiplicative inverse of 105.
  1.    - 50
  2.    0.00001
  3.    - 100000
  4.    100000
 Discuss Question
Answer: Option D. -> 100000
:
D
105
= 1105
= 1100000
When a number is multiplied with its multiplicative inverse, the result is 1. To make the given number, which is 1100000, equal to 1, we need to multiply it with 100000, which is the reciprocal of 1100000.
Therefore, 100000, or 105 is the multiplicative inverse of 105.
Question 17. The value of 1000 is 1000.
  1.    True
  2.    False
  3.    2.16×105   
  4.    216×1000000
 Discuss Question
Answer: Option B. -> False
:
B
Note that a0=1 for any a0
Thus, the value of1000is 1.
Question 18. If m and n are integers, a is a non-zero integer and am × an =ax, then the value of x is _____. 
  1.    mn
  2.    m+n
  3.    m−n
  4.    mn 
 Discuss Question
Answer: Option B. -> m+n
:
B
We have am×an=am+n,​​ where a, m and n are integers, a0.
Given am×an=ax
am+n=ax
x=m+n
Question 19. Evaluate the exponential expression x5 × x4, for x = 2.
  1.    32
  2.    128
  3.    256
  4.    512
 Discuss Question
Answer: Option D. -> 512
:
D
x5 × x4, for x = 2
Substituting 2 in place of x
= 25× 24
= 29(am×an=am+n) = 512
Question 20. (4×103+3×1+1×101+6×100)=
___
 Discuss Question

:
4×103+3×1+1×101+6×100=(4×1000)+(3×1)+110+(6×1)=4000+3+0.1+6=4009.1

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