Answer:
(a) N{A∩B} = 0
(b) N{A∪B} = 9
Explanation:
Union of two sets: This can be defined as the sum of all the elements of the two sets without writing one element twice. it is denoted by the symbol ∪
Intersection of two sets; This is the set of elements that appears in both sets. It is denoted by the symbol ∩
From the question above,
assuming there is no repetition element in both set,
(a) The smallest number possible for N{A∩B} = 0
(b) The largest number possible for N{A∪B} = 4+5 = 9.