If 1 = 5, 2 = 25, 3 = 325, 4 = 4325 Then 5 =?

Question

If
1=5,
2=25,
3=125,
4=625
then
5=??

Answer 1

5=1 because 1=5.

Answer 2

5 = 54325

Logic: Last digit is 5 and previous digits are n (n-1) (n-2) ..till 2.