Union & Intersection

Pre-Calculus Tutorial

Union & Intersection


Union, denoted by ∪, means the inclusion of ALL elements in a set.

Interxection, denoted by ∩, is the inclusion of elements that are the SAME.

Easy way to Remember:
Union is ALL Elements, pretty easy ?
Intersections is finding the same ones.

Let’s try an example!

Sample Problem

Set A = {A,E,I,O,U}
Set B = {A,B,C,D,E}

Find A ∪ B and A ∩ B


A ∪ B = {A,B,C,D,E,I,O,U} * Remember to write each element once in order. If they
were numbers, we would put them in numerical order

Step 1: Find all elements that are common in both sets. In this case the common letter of Set A and Set B are elements A and E. Therefore the intersection is…

A ∩ B = {A, E}

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