Numerele :1,2,3,...,60,61 apartin multimii A.
Numerele: 3,4,5,6,...9,10,11 aparin multimii B.
Numerele:1,11,111,1111... apartin multimii C.
Numerele: 2,4,6,8,...,30,32,34 apartin multimii D.
Numerele: 71,73,75,77,...,101,103 apartin multimii E.
Doua multimi similare sunt: F={11,22,33,44,...,88,99}=Numerele:11,22,33,44,...,88,99 apartin multimii F.G={90,100,110,120,...,180,190}=Numerele:90,100,110,120,...,180,190 apartin multimii G.