multiple

x is a multiple of 6 and 1 ≤ x ≤ 16. We want multiples of 6 between 1 and 16. We start with 6. Another multiple of 6 is 12 The next multiple of 6 is 18, which is out side the range of 1 ≤ x ≤ 16. So our number set is x = {6, 12}