Question 1206205
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I'm not sure if you posted a screenshot, but your diagram isn't showing up. 


This is probably what your Venn Diagram looks like
{{{
drawing(400,400,-5,5,-5,5,
line(-4,4,4,4),
line(4,4,4,-4),
line(4,-4,-4,-4),
line(-4,-4,-4,4),

circle(-1,1,2),circle(1,1,2),circle(0,-0.7321,2),

locate(-3.5,4.4,U),
locate(-2.8,2.8,A),
locate(2.6,2.8,B),
locate(1,-2.6,C),
locate(-2,1.8,"I"),
locate(0,1.8,"II"),
locate(2,1.8,"III"),
locate(-1.5,0,"IV"),
locate(0,0.4,"V"),
locate(1.2,0,"VI"),
locate(0,-1.5,"VII"),
locate(3,-1.5,"VIII")
)
}}}
If my assumption is incorrect then please let me know.


U={1,2,3,...,11,12,13} is the universal set


Inside the universal set are these subsets
A={3,5,7,8,9,11}
B= {4,5,6,9,10}
C={1,3,4,5,6,7,10,12}
we have n = 3 subsets and 2^n = 2^3 = 8 distinct regions.


Let's form the following table
<table border = "1" cellpadding = "5"><tr><td>U</td><td><font color=blue>1</font></td><td><font color=blue>2</font></td><td><font color=blue>3</font></td><td><font color=blue>4</font></td><td><font color=blue>5</font></td><td><font color=blue>6</font></td><td><font color=blue>7</font></td><td><font color=blue>8</font></td><td><font color=blue>9</font></td><td><font color=blue>10</font></td><td><font color=blue>11</font></td><td><font color=blue>12</font></td><td><font color=blue>13</font></td></tr><tr><td>A</td><td></td><td></td><td>3</td><td></td><td>5</td><td></td><td>7</td><td>8</td><td>9</td><td></td><td>11</td><td></td><td></td></tr><tr><td>B</td><td></td><td></td><td></td><td>4</td><td>5</td><td>6</td><td></td><td></td><td>9</td><td>10</td><td></td><td></td><td></td></tr><tr><td>C</td><td>1</td><td></td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td></td><td></td><td>10</td><td></td><td>12</td><td></td></tr></table>
The top row represents the universal set.
Then sets A,B,C are the next three rows.
I've spaced things out so that the items line up.


Then go through each column one at a time to sort out the values. 


The number "1" is found in set C only.
So we'll write "1" in region VII aka region 7.
This is in circle C and outside the other circles.


The number "2" is not in any of the three sets. 
This value is written outside of the circles (region VIII aka region 8).


The number "3" is found in sets A and C, but not in set B. 
Write this value in region IV aka region 4.


Keep this process going until you've reached the right-most edge of the table.


This is what you should get when filling out the Venn Diagram
{{{
drawing(400,400,-5,5,-5,5,
line(-4,4,4,4),
line(4,4,4,-4),
line(4,-4,-4,-4),
line(-4,-4,-4,4),

circle(-1,1,2),circle(1,1,2),circle(0,-0.7321,2),

locate(-3.5,4.4,U),
locate(-2.8,2.8,A),
locate(2.6,2.8,B),
locate(1,-2.6,C),
locate(-2,1.8,"8,11"),
locate(0,1.8,"9"),
locate(-1.5,0,"3,7"),
locate(0,0.4,"5"),
locate(1.2-0.5,0,"4,6,10"),
locate(0,-1.5,"1,12"),
locate(3,-1.5,"2,13")
)
}}}
Notice region III has no values in it. 
This is because there aren't any values in set B only.
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