CASE I
MULTIPLICANT AND MULTIPLIER SHOULD BE SAME NOS.
STEP 1. Reduce the no. by 1
STEP 2. Then subtract the result by 9 series
e.g.1- 83 X 99
82
9-8 =1
9-2=7
Finally the answer will be 8217
e.g. 2 - 402 x 999
401
9-4 =5
9-0=9
9-1=8
Finally the answer will be 401598
e.g. 3 - 17825 x 99999
17824
9-1 =8
9-7=2
9-8=1
9-4=5
Finally the answer will be 1782482175