Page 48 - Start Up Mathematics_8 (Non CCE)

2. If x and y are two non-zero rational numbers and m and n are any two integers, then
x () m
m
n
n
m
(a) (x) × (x) = (x) m + n (b) = (x) ÷ (x) = (x) m – n
x () n
 x  n x () n
n
n
m n
(c) (x ) = (x) mn (d)   = n (e) (x) × (y) = (xy) n
y
  y ()
 x  − n  y  n y () n
3. If is any non-zero rational number and n is a positive integer, then   =   = .
y
   x  x () n
n
4. Standard form of any number = (A number between 1 and 10) × (10) ; where n is any integer
Review Exercises
Multiple ChoiCe Questions
2
(
–5
1. The value of (2) × 64 3 ) is:
(a) 512 (b) 1 (c) 16 (d) 1
512 2
−3

   −   2
2
2.     is equal to:
   3   
(a) 3 (b) 64 (c) 81 (d) 729
2 729 32 64
 2 4
− 
3. Which of the following is not equal to   ?
 5 
2 4  2 −   2 −  − ( ) 2 4 () 2 4
−   2
−   2
(a) (b)         (c) (d) −
×
×
×
− ( 5) 4  5   5   5   5  () 5 4 () 5 4
− 
− 
4.  2  −6 ÷  2  4 is equal to:


 7   7 
− 
− 
− 
− 
(a)  2  2 (b)  2  −10 (c)  7  −10 (d)  7  2




 7   7   2   2 
–1
–1
–1
5. {(4) – (2) } × (3) is equal to:
(a) −1 (b) 1 (c) 3 (d) −3
12 12 8 8
solve Mentally
True or False
–11
1. The standard form of 0.0000000000942 is 9.42 × (10) .
2. The value of m for which   6  − 4 ×   6   3m =  6   5 is –3.


 13   13   13 
3. If {(2) 3m – 1 + 10} ÷ 7 = 6, then m is 2.
4
4. The usual form of 6.8 × (10) is 6,80,000.
18
55
97
60
5. The value of (2) × (2) – (2) × (2) is 0.
40