Intersection and Union of Sets

Objectives Understand the difference between intersection and union of sets. Identify the intersection and the union of sets.

Intersection and Union of Sets A set is a group of distinct objects or data of some kind. A set can contain any kind of data from names to numbers to places. In math, sets normally contain numbers in the form of data.

Intersection and Union of Sets The intersection of two sets are the elements that occur in both sets. The intersection of sets is denoted with the ∩. Mathematically, it will appear as A ∩ B. If we are to think in terms of “English” we would say “the intersection of set A and B. *We can think of the ∩ as “and”.

Intersection and Union of Sets The union of two sets are the elements that occur in one set or in the other sets. The union of sets is denoted with the ∪. Mathematically, it will appear as A ∪ B. If we are to think in terms of “English” we would say “the union of set A or B. *We can think of the ∪ as “or”.

Intersection and Union of Sets To visualize the intersection and union of two or more sets we can use a venn diagram. For instance, suppose Set x = {6, 5, 14, 7, 12} Set y = {5, 17, 6, 9, 8, 11} X ∩ Y = {5,6} 17 11 8 9 14 12 7 5 6 X ∪ Y = {5,6,7,8,9,11,12,14,17}

Henry Ana Example - Intersection and Union of Sets Green Blue Black Given the venn diagram identify the colors that Ana likes to use in her art and the colors that Henry likes to use. Tan Brown Green White Black Red Blue Henry Ana Ana = {Black, Blue, Red, White} Henry = {Blue, Brown, Green, Red, Tan}

Henry Ana Example - Intersection and Union of Sets Green Blue Black Given the venn diagram identify the intersection and the union of Ana’s and Henry’s color palette. Tan Brown Green White Black Red Blue Henry Ana Henry ∩ Ana = {Blue, Red} Henry ∪ Ana = {Black, Blue, Brown, Green, Red, Tan, White}

Example - Intersection and Union of Sets The given venn diagram shows the sports that three students play throughout the year Ed Mia Mike Hockey Golf Tennis Cross Fit Badminton Basketball Softball Wrestling Baseball Boxing

Basketball!!!  Example - Intersection and Union of Sets Answer the following questions. 1) Identify the set of sports that Mia and Ed enjoy. {Basketball, Tennis} 2) Identify the set of sports that Mia enjoys. {Basketball, Cross Fit, Hockey, Softball, Tennis} 3) Identify the set of sports that Mike or Ed enjoy. {Badminton, Basketball, Baseball, Boxing, Golf, Softball, Tennis, Wrestling} 4) Identify the set of sports that Mike, Ed, and Mia all enjoy. {Basketball} 5) Identify the most liked sport. Basketball!!! 

4.3 Intersection and Union of Sets Summarize Notes Read section 4.3 Homework Worksheet