NCERT Class 7 Mathematics

260 MATHEMATICS

(ii)

23 2

94

45

2 =

45

222

2×3 ×2

3× 2

=

54

222

2×2 ×3

=

15 4

42

2×3

2×3

=

64

42

2×3

2×3=

2×3^64  42

=2^2 × 3^2 = 4 × 9 = 36

Note: In most of the examples that we have taken in this Chapter, the base of a power

was taken an integer. But all the results of the chapter apply equally well to a base

which is a rational number.

EXERCISE 13.2

1. Using laws of exponents, simplify and write the answer in exponential form:
   (i) 3^2 × 3^4 × 3^8 (ii) 6^15 ÷ 610 (iii) a^3 × a^2

(iv) 7x×7^2 (v)

233

55 (vi) 2^5 × 5^5

(vii) a^4 × b^4 (viii)  

4 3

3 (ix) 22 2^20 ^153

(x) 8t÷ 82

2. Simplify and express each of the following in exponential form:

(i) 23 4

332

34

(ii) 5×5 5^2473 (iii) 25435

(iv)

28

3

37 11

21 11





(v)

7

43

3

33 

(vi) 2^0 + 3^0 + 4^0

(vii) 2^0 × 3^0 × 4^0 (viii) (3^0 + 2^0 ) × 5^0 (ix)

85

33

2

4

a

a





(x)

(^58)
3 ×
a
a
a
(xi)
4
4
583
552
ab
ab
(xii)  
3 2
22 

3. Say true or false and justify your answer:
   (i) 10 × 10^11 = 100^11 (ii) 2^3 > 5^2 (iii) 2^3 × 3^2 = 6^5
   (iv) 3^0 = (1000)^0