business mathematics

Union of sets:
If A and B are two sets, the union of A and B is the set of all those elements which belong to either A or B or both A and B and is denoted by A ⋃ B.
A ⋃ B = {x| x Є A or x Є B}
If A ⊂ B, then A ⋃ B = B
A ⋃ Φ = A
A ⋃ μ = μ

Intersection of Sets:
Let A and B, be two sets. The intersection of A and B is the set of all those elements that belong to A and B. It is denoted by A ⋂ B.
A ⋂ B = {x | x Є A and x Є B}
If A ⊂ B, then A ⋂ B = A
A ⋂ Φ = Φ
A ⋂ μ = A

Difference of Sets:
Let A and B be two sets. The difference of A and B, denoted by A - B, is the set of all those elements of A which do not belong to B.
A – B = {x| x Є A and x∉ B} = { x Є A | x ∉ B}
Similarly, B – A = { x Є B | x ∉A}
Example:
A = {4,5,6,7}, B = {6,7,8,10}
A – B = {4,5}
B – A = {8,10}