 # Important questions for Exponents Class 8 Chapter 12 CBSE

In this page we have Important questions for exponents Class 8 maths Chapter 12 CBSE . Hope you like them and do not forget to like , social share and comment at the end of the page.
Question 1
Evaluate
1. 2 -2
2. (- 2) - 2
3.  (3/2)-5

As we know that
b-n= 1/bn
(i)  2-2  =  1/ 22  =1/4
(ii) (-2)-2  = 1/(-2)2= 1/4
(iii) (3/2)-5   =3-5/ 2-5 =25/35   = 32/243
Question 2
Simplify and express the result in power notation with positive exponent.
(i) (-2)5 ÷   (-2)4
(ii) (1/2)2 × (2/5)2
(iii) (-5)2 × (3/5)

(i)  (-2)5 ÷   (-2)4
= (-2)5 / (-2)4
= (-2)5-4
=-2
(ii) (1/2)2 × (2/5)2
=   (1/4) X   (4/25)
= 1/25
iii) (-5)2 × (3/5)
=25 × (3/5) =15
Question 3
Find the value of.
1. (40 + 4 - 1) × 22
2.  (3 - 1 × 9 - 1)  ÷ 3 - 2
3. (11 - 1 + 12 - 1 + 13 - 1)0

1. (40 + 4 - 1) × 22 = (1+1/4) × 4
= 4+1=5
2. (3 - 1 × 9 - 1)  ÷ 3 - 2 = [(1/3) × (1/9)] ÷ (1/9)
=1/3
3. (11 - 1 + 12 - 1 + 13 - 1)0
=1   as  a0 =1
Question 4
Find the value of   x here
(11/9)3   x  (9/11)6  = (11/9)2x-1

(11/9)3   x (11/9)-6  =  (11/9)2x-1
(11/9)3-6  =  (11/9)2x-1
-3=2x-1
Or
x=-1

Question 5
Find the value of m for which 2m   ÷  2-4 = 45
2m   ÷   2-4 = 45
2m × (1/2-4)  = 210
2m+4 =210
So  m+4=10
m=6
Question 6
Express the following numbers in standard form.
(i) 0.0000000015 (ii) 0.00000001425
(iii) 102000000000000000

1. 0.0000000015 =1.5 ×10-9
2. 0.00000001425
=1.425×10-8
3. 102000000000000000
=1.02×1017
Question 7
Express the following numbers in usual form.
(i) 34.02 x 10-5 (ii) 9.5 x 105
(iii) 9 x 10-4 (iv) 2.0001 x 108

1. 34.02 x 10-5 = .0003402
2. 9.5 x 105
=950000
3. 9 x 10-4
=.0009
4. 2.0001 x 108
=200010000

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Reference Books for class 8 Math

Given below are the links of some of the reference books for class 8 Math.

1. Mathematics Foundation Course for JEE/Olympiad : Class 8 This book can take students maths skills further. Only buy if child is interested in Olympiad/JEE foundation courses.
2. Mathematics for Class 8 by R S Aggarwal Detailed Mathematics book to clear basics and concepts. I would say it is a must have book for class 8 student.
3. Pearson Foundation Series (IIT -JEE / NEET) Physics, Chemistry, Maths & Biology for Class 8 (Main Books) | PCMB Combo : These set of books could help your child if he aims to get extra knowledge of science and maths. These would be helpful if child wants to prepare for competitive exams like JEE/NEET. Only buy if you can provide help to the child while studying.
4. Reasoning Olympiad Workbook - Class 8 :- Reasoning helps sharpen the mind of child. I would recommend students practicing reasoning even though they are not appearing for Olympiad.

You can use above books for extra knowledge and practicing different questions.

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