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How Do You Find a Union and Intersection from a Venn Diagram?

Use this Venn Diagram to find: a) A union B b) B intersect C

Summary

  1. A, B, and C are sets
  2. The three overlapping circles are called a Venn Diagram
  3. Each set is represented by a circle in the Venn Diagram
  4. The numbers inside each circle are the elements of that set
  5. The U symbol in A U B means 'union'
  6. The union of A and B is all the elements in either A or B
  7. The upside down U symbol means 'intersection'
  8. The intersection of B and C is all the elements in both B and C

Notes

    1. This reads "A union B"
    2. A and B are sets
    3. Their union is the set of all numbers in either A or B
    1. A and B are sets
    2. Elements are the numbers in the set
    1. A and B are sets
    2. Elements are the numbers in the set
    3. Their union is the set of all numbers in either A or B
    1. A is a set
    2. Elements are the numbers in the set
    3. All the elements in A are in the union of A and B
    4. 7, 1, 6, and 5 are the elements of set A
    5. So they are all in the union of A and B
    1. B is a set
    1. When you're writing out a union, you only need to write each element once, even if it occurs in both sets
    2. So we don't have to write down 5 and 6 again
    1. Elements are the numbers in the set
    2. 3, 2, and 9 are the elements of set B that are not already in our union
    3. So we add them to what we already have
    1. A union B is the set of all elements in either A or B
    2. So we have 7, 1, 6, 5, 3, 2, and 9
    1. This reads "B intersect C"
    2. B and C are sets
    3. The intersection is the set of all numbers in both B and C
    1. B and C are sets
    2. Elements are the numbers in the set
    3. The intersection is the set of all numbers in both B and C
    1. B and C are sets
    2. Elements are the numbers in the set
    1. B and C are represented by circles on the Venn Diagram
    2. Where they overlap is their intersection
    1. You can figure out the intersection by looking at what numbers are in the overlap
    2. Here, 6 and 3 are in the overlapping part of B and C
    3. This means they will be in the intersection
    1. Braces are the curly brackets that contain sets
    2. 6 and 3 are in the overlapping part of B and C on the Venn Diagram
    3. So 6 and 3 are the elements of the intersection
    1. B intersect C is the set of all elements in both B and C
    2. So our set contains the elements 6 and 3