The expression Z5 means the fifth element of the set of integers starting at Z (which is 2 in this case) and incrementing by 1.
So, starting at 2, we can count up 5 elements to find Z5:
2, 3, 4, 5, 6
Therefore, Z5 is equal to 6.
So, evaluating the expression for z = 2, Z5 = 6.