Question

Show that 12n cannot end with digit 0r 5 for any natural number n

Answer 1

12^1 end's with the digit 2
12^2end's with the digit 4
12^3 end's with the digit 8
12^4ends with the digit 6
12^5 end's with the digit 2

it is again & again comes in the place of units
so, 12^n doesn't end's with the digits 0,5