When the elements in the set s are all natural numbers and satisfy the proposition "if x belongs to s, then 8-x belongs to s", how many sets S satisfy the above conditions When the elements in the set s are all natural numbers and satisfy the proposition "if x belongs to s, then 8-x belongs to s", how many sets S satisfy the above conditions, please write them all! I don't know the answer on the first floor

When the elements in the set s are all natural numbers and satisfy the proposition "if x belongs to s, then 8-x belongs to s", how many sets S satisfy the above conditions When the elements in the set s are all natural numbers and satisfy the proposition "if x belongs to s, then 8-x belongs to s", how many sets S satisfy the above conditions, please write them all! I don't know the answer on the first floor

{0,8}
{1,7}
{2,6}
{3,5}
{4}
{0,1,7,8}
{0,2,6,8}
{0,3,5,8}
{0,4,8}
{1,2,6,7}
{1,3,5,7}
{1,4,7}
{2,3,5,6}
{2,4,6}
{3,4,5}
{0,1,2,6,7,8}
{0,1,3,5,7,8}
{0,1,4,7,8}
{0,2,3,5,6,8}
{0,2,4,6,8}
{0,3,4,5,8}
{1,2,3,5,6,7}
{1,2,4,6,7}
{1,3,4,5,7}
{2,3,4,5,6}
{0,1,2,3,5,6,7,8}
{0,1,2,4,6,7,8}
{0,1,3,4,5,7,8}
{0,2,3,4,5,6,8}
{1,2,3,4,5,6,7}
{0,1,2,3,4,5,6,7,8}