SETS/ DISJOINT

DISJOINT SETS

FOCUS QUESTION: 

What are the special symbols and language I use when I work with sets?

 

SPECIFIC OBJS. By the end of the lesson students should be able to:

1.  Name and list members in the intersection or union of two sets.

2.   Define “disjoint sets”.

 CONTENT SUMMARY

In other words, the two sets have no common elements/members.

ENGAGE

Students  I want you to examine the Venn diagrams below, then tell me what is the difference between the two representations of Sets A and B.

Why was there an overlap in the first Venn diagram?

Why was there no overlap in the second Venn diagram?

EXPLORE

Well by now you should have realized that the first  two sets had "a" and "b" as common elements and so there was an overlap of the two circles to show the elements common to both sets.

On the other hand, the second Venn diagram depicted two separate circles because the elements or members of the two sets A and B had no common elements.

Now this type of set is referred to as a  DISJOINT SET.

You can watch this video clip to glean more information.

EXPLAIN

Now can you explain what a disjoint set is?

EXTEND

Write a scenario that would be represented by disjoint sets.

EVALUATION

1. Examine the diagram below carefully, then answer the question that follows:

Which of the following represents the Venn diagram above?

(a) U= {1, 2, 3, 4, 5, 6, 7, 8, 9}

      A={1, 2, 5, 6}

      B={3, 9}

(b) U=(4, 7, 8}

      A={1, 2, 6, 5, 8}

      B={3,4,9}

(c) U={ 7, 8, 9}

      A={1, 2, 3, 4, 5, 6, 7, 8, 9}

      B={3,  4, 7, 8}

2. Consider the sets below:

    M={odd numbers between 0 and 10}

    V= {prime numbers between 1 and 12}

                      and

    J= {1, 4, 6, 13}

   K= {2, 5, 7, 10}

Draw the two Venn diagrams to represent the sets. Which is the example of a disjoint set?