If A and B are two sets such that A ⊂ then what is A U B?

Find the following sets find their union:
(i) A = {a,e,i,o,u}; B = {a,b,c}.
(ii) X = {1,3,5}; Y = {1,2,3}.
(iii) A = {x: x is a natural number and multiple of 3.};
     B = {x : x is a natural number less than 6.}.
(iv) A = {x: x is a natural number and 1 < x < 6.};
       B = {x : x is a natural number and 6 < x < 10.}.
(v) A = {1,2,3}; B = φ.

Let A = {a, b}, B = {a,b, c}. Is A ⊂ What is A U B?

If A = {1,2,3,4} , B = {3,4,5,6}, C = {5,6,7,8} and D = {7,8,9,10}; find
(i) AB (ii) AC (iii) BC (iv) B D
(v) ABC (vi) ABD (vii) BC D

If A = {3, 5, 7, 9, 11}, B = {7, 9, 11, 13}, C = {11, 13, 15} and D = {15, 17}; find
(i)  A ∩ B
(ii)  B ∩ C
(iii)  A ∩ C ∩ B
(iv)  A ∩ C
(v)   B ∩ D
(vi)  A ∩ (B ∩ C)
(vii) A ∩ D
(viii) A ∩ (B ∩ D)
(ix)  (A ∩ B) ∩ (B ∪ C)
(x)  (A ∪ B) ∩ (B ∪ C)