Answers

2014-04-29T20:53:17+05:30
7=7(mod 10)
7^2=49(mod 10)
     =-1(mod 10)
7^105=7*7^104
        =7*(49)^52
        =7*(-1)^52(mod 10)
        =7(mod 10)

therefore units digit of 7^105 is 7.
1 5 1
2014-04-30T20:22:58+05:30