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### Mathematics For Class 8

### 1.1 Sets

Set is a well-defined collection of distinct objects. Sets are usually denoted by capital letters of English alphabet. Some examples are:

(1) A = Set of first six prime numbers | (Descriptive form) |

(2) B ={1, 2, 3, 4, 5} |
(Tabular form) |

(3) C = {x/x ∈ Ζ^{∧} -5 < x < 5} |
(Set-builder form) |

**Revision Exercise I**

**1.** Write the following sets in tabular and set builder forms.

- A= Set of first five natural numbers
- B= Set of integers between -2 and 3.
- C=Set of prime numbers between 10 and 30.

**2. **From the sets given below identify and write:

- Finite sets
- Infinite sets

A= {1,2,3,omposite numbers between 10 and 30.

D= Set of a4,5} B={1,3,5,7,...}

C= Set of all multiples of 10 , E = {*x/x* ∈ Z A *x *<0}