因为{2,-2}包含于S,所以2∈S,且-2∈S.
由2∈S,则1÷(1-2)=-1∈S,则1÷(1-(-1))=1/2∈S,则1÷(1-1/2)=2∈S.
由-2∈S,则1÷(1-(-2))=1/3∈S,则1÷(1-1/3)=3/2∈S,则1÷(1-3/2)=-2∈S.
所以S={2,-2,-1,1/2,1/3,3/2}.
因为{2,-2}包含于S,所以2∈S,且-2∈S.
由2∈S,则1÷(1-2)=-1∈S,则1÷(1-(-1))=1/2∈S,则1÷(1-1/2)=2∈S.
由-2∈S,则1÷(1-(-2))=1/3∈S,则1÷(1-1/3)=3/2∈S,则1÷(1-3/2)=-2∈S.
所以S={2,-2,-1,1/2,1/3,3/2}.