Question

Show that 7^th cannot end with the digit zero for any natural number n

Answer 1

Answer:

If 7n has to end with the digit 0 for any natural number n, then it has to be divisible by 10. ... its prime factorisation should have the factors of both 2 and 5 [ since 10=2x5 ] But we know that 7=7x1 By the fundamental theorem of arithmetics, we also know that there exist no other factors for 7.