Answer:
Option B
Explanation:
If you look into the power of 7 then you will notice a sequence:
71=7,72=49, 73=343, 74=2401, 75=16807
And the unit digits keep on repeating as { 7, 9, 3, 1 } It repeats after every 4 powers ,
So divide 95 by 4 You will get 3 as the remainder . The third number in the series is 3. This implies the unit digit of 795 is 3 .
Similarly, do for 358
31=3, 32=9, 33=27, 34=81, 35=243 And the unit digits keep on repeating as { 3, 9, 7, 1 } Now divide 58 by 3 and get the remainder as 2 Second number in the series is 9.
This implies unit digit of 358 is 9
Unit digit of 795−358 = 3−9 = 13-9 (borrow from the previous digit)
= 4
