IfA = {3, 6, 9, 12, 15, 18, 21}, B = {4, 8, 12, 16, 20},
C= {2, 4, 6, 8, 10, 12, 14, 16}, D = {5, 10, 15, 20}; find
(i) A– B
(ii) A– C
(iii) A– D
(iv) B – A
(v) C– A
(vi) D– A
(vii) B – C
(viii) B– D
(ix) C– B
(x) D– B
(xi) C– D
(xii) D– C