D₁₂ ={ 1, 2, 3 ,4 ,6 ,12}
B ={ 1, 3, 5, 7, 9 , 11}
C ={ 0, 2, 4, 6, 8, 10}
a )D₁₂ in reuniune cu B ={ 1,2,3,4,5,6,7,9,11,12}
b)D₁₂ in intersectie cu C ={ 2,4,6}
c)B in intersectie cu C = multimea vida ( sper ca stii semnul )
d)D₁₂ \ B ={ 2,4,6,12}
e) D₁₂ \ C ={ 1,3,12}