**Greatest Common Factors Workbook**

**Odd numbers :** The numbers ending with 1,3,5,7 or 9 are known as odd numbers.

**Even numbers :** the numbers ending with 2,4,6,8 or 0 are known as even numbers.

**Prime and composite numbers**

**Prime Number:**

Let ‘p’ be a natural number ‘p’ is said to be prime if it has exactly two distinct factors, namely 1 and itself.

e.g., 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, …..

There are 25 prime numbers between 1 and 100. These are:

2, 3, 5,7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 & 97.

**Composite Number:**

Let ‘a’ be a natural number, ‘a’ is said to be composite if, it has atleast three distinct factors.

**Note:**

(i) ‘1’ is neither prime nor composite.

(ii) ‘2’ is the only even prime number.

(iii) Number which are not prime are composite numbers (except 1).

(iv) ‘4’ is the smallest composite number.