Q={1,3,9} \mathrm Q = \{1, 3, 9\}Q={1,3,9}
Q={3,9} \mathrm Q = \{3, 9\}Q={3,9}
Q={1,3} \mathrm Q = \{1, 3\}Q={1,3}
Q={3,9,18} \mathrm Q = \{3, 9, 18\}Q={3,9,18}