Count how many zeros are at the end of your int:
def end_zeros(num): s = str(num) return len(s) - len(s.rstrip("0")) print(end_zeros(10)) # == 1 print(end_zeros(101)) # == 0 print(end_zeros(245)) # == 0 print(end_zeros(100100)) # == 2 ---------------- Writing a loop (using % and // ) feels like [reinventing the wheel] and seems intrinsically wrong. i like this code (above) because it's not reinventing the wheel --- the Python implementor has already done the loop (using % and // ), so i'm just using that efficient tool (routine). -- https://mail.python.org/mailman/listinfo/python-list