Given sets are A = {3, 6, 9, 12, 15, 18, 21}

B = {4, 8, 12, 16, 20}

C = {2, 4, 6, 8, 10, 12, 14, 16} and

D = {5, 10, 15, 20}

(i) A – B

A – B = {3, 6, 9, 12, 15, 18, 21} – {4, 8, 12, 16, 20} = {, , , , , }

(ii) A – C

A – C = {3, 6, 9, 12, 15, 18, 21} – {2, 4, 6, 8, 10, 12, 14, 16} = {, , , , }

(iii) A – D

A – D = {3, 6, 9, 12, 15, 18, 21} – {5, 10, 15, 20} = {, , , , , }

(iv) B – A

B – A = {4, 8, 12, 16, 20} – {3, 6, 9, 12, 15, 18, 21} = {, , , }

(v) C – A

C – A = {2, 4, 6, 8, 10, 12, 14, 16} – {3, 6, 9, 12, 15, 18, 21} = {, , , , , }

(vi) D – A

D – A = {5, 10, 15, 20} – {3, 6, 9, 12, 15, 18, 21} = {, , }

(vii) B – C

B – C = {4, 8, 12, 16, 20} – {2, 4, 6, 8, 10, 12, 14, 16} = {}

(viii) B – D

B – D = {4, 8, 12, 16,20} – {5, 10, 15, 20} = {, , , }

(ix) C – B

C – B = {2, 4, 6, 8, 10, 12, 14, 16} – {4, 8, 12, 16, 20} = {, , , }

(x) D – B

D – B = {5, 10, 15, 20} – {4, 8, 12, 16, 20} = {, , }