Question

If A = {2, 4, 6, 8, 10…} and B = {1, 3, 5, 7, …}, what is A ∩ B?

{2, 4, 6, 8, ….}

{ }

{1, 2, 3, 4, 5, …}

{1, 3, 5, 7, ….}

Answer 1

A ∩ B means that you find nothing that belongs to A or B in this group
A ∩ B is also A ∪ B's opposite :)

Answer 2

A ∪ B is {1, 2, 3, 4, 5, …}

Opposite of A ∪ B (A ∩ B) would be the opposite of {1, 2, 3, 4, 5, …} and since
\[A \in \mathbb{N}\]\[B \in \mathbb{N}\]
A ∩ B would be { }