[Hello, rspierz!

You could draw a Venn diagramHow many elements are in the union of four sets

if each of the sets has 100 elements,

each pair of the sets shares 50 elements,

each three of the sets share 25 elements,

and there are 5 elements in all four sets?

. . (if you know how to draw one withsets).four

You should be familiar with these two Union Formulas:

But you may not be aware of this one:

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