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