Có 16 tập hợp con đó là :
A = \(\left\{1\right\};\left\{2\right\};\left\{3\right\};\left\{4\right\}\) ; \(\left\{1;2\right\},\left\{1;3\right\},\left\{1;4\right\},\left\{2;3\right\},\left\{2;4\right\},\left\{3;4\right\};\left\{1;2;3\right\},\left\{1;2;4\right\},\left\{1;3;4\right\},\left\{2;3;4\right\},\left\{1;2;3;4\right\}\) ; \(\left\{\varnothing\right\}\)
{ 1 } , { 2 } , { 3 } , { 4 }
{ 1; 2 } , { 1; 3 } , { 1; 4 } , { 2; 3 } , { 2; 4 } , { 3; 4 }
{ 1; 2; 3 } , { 1; 2; 4 } , { 1; 3; 4 } , { 2; 3; 4 }
{ 1; 2; 3; 4 } , ∅