Question

7^95-3^58 then find its unit place

Answer 1

to find unit digit 
7^95 
divide index 95 by 4 find remainder. 
as the cycle always repeats after 4 
e.g. 
2^1 = 2, 2^2 = 4, 2&3 = 8, 2^4 = (1)6, 2^5 = (3)2 
cycle is 
2, 4, 8, 6 2, 4 ... etc. 
95/4 = 23 3/4 Remainder is 3 
so unit digit in 7^95 = unit digit of 7^3 = (34)3 
unit digit in 3^58 
58/4 = 14 2/4 remainder is 2 
unit digit in 3^58 = unit digit of (3)^2 = 9 

3 – 9 = 13 – 9 = 4