Is 8505 even or odd

Answer 1

All odd numbers end with one of {1, 3, 5, 7, 9} (the odd digits)

as 8505 ends with a 5 which is one of {1, 3, 5, 7, 9} it is an odd number.

Answer 2

8505 ÷ 2 = 4252 remainder 1 which means that 8505 is an odd number as there is a remainder.
Note, a number that can be divided by 2 and without a remainder is an even number.