**Sets:**

A **Set** is made up of a specific group of objects or symbols.

(The objects or symbols are called the **Elements** of the Set)

Example:

If a set E consists of even numbers, then

E = { 2, 4, 6, 8, … }

Set E is an **Infinite Set**.

If a set S is made up of the countries of South America, then

S = { Brazil, Chile, Argentina, …}

Set S is a **Finite Set**.

*image: decodeunicode.org*

**Subsets:**

If all the Elements of Set X are also Elements of another Set Y, then

X is a **Subset** of Y.

Example:

If X = { sun, moon } and Y = { sun, moon, earth }, then

X C Y

*image: fanpop.com*

**Empty set:**

If Set A does not have any Elements in it , then it is called an **Empty Set** and is represented by the symbol Ø

A = Ø

(The Empty Set is a Subset of all Sets)

*image: cnx.org*

**Universal Set:**

The Universal Set contains all Elements in the problem under consideration.

**Complement of a Set:**

If U is the Universal Set containing Set A , then

the Complement of Set A is the set of elements which are in U , but not in A

Example:

If U = { 11, 13, 15, 17, 19 } and A = { 11, 13, 15 }

A’ = { 17, 19 }

The Complement of the Universal set is the Empty set.

U’ = Ø

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