If A = {x:x<6,x€N} and B ={y:y<4,y€W}, list A-B and B-A
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Answers:

Explanation:

Recall the following

N = set of natural numbers

N = {1,2,3,4,5,6,...}

W = set of whole numbers

W = {0,1,2,3,4,5,6,...}

The sets N and W are nearly the same set, except for W has 0 involved, while N does not. The triple dots say that pattern goes on forever.

From those infinite sets, we form the two finite subsets A and B like so

A = {x : x < 6, x is in N}

A = {x such that x < 6 and x is a natural number}

A = {1,2,3,5}

B = {y : y < 4, y is in W}

B = {y such that y < 4 and y is a whole number}

B = {0,1,2,3}

In short, we have these two finite sets

The notation A-B indicates we'll start with set A and kick out members of set B that are also in set A. This is known as set subtraction.

So we'll write out set A to get {1,2,3,4,5}

Then we cross off 1,2,3 in this set because these values are found in set B

We're left with {4,5}

Therefore A-B = {4,5}

To compute B-A, we do the same idea but in reverse.

Start with set B

{0,1,2,3}

and erase the items 1,2,3 since they are found in set A

We then find that

B-A = {0}

Even though we have 1 item, don't forget about the curly braces to say we have a set. Any set that has exactly 1 item in it is considered a singleton set.

Keep in mind that the singleton {0} is not the empty set. The empty set would have nothing inside it and we would say { } instead.

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