**Factorisation of Numbers Workbook-1**

Factors are the numbers that are multiplied to give a product.

If a number ‘a’ is divided by ‘b’ and remainder is zero than ‘b’ is said to be factor of ‘a’

**Co-Prime Numbers:**

Two numbers (not necessarily prime) are co-prime, if they have only 1 as common factor.

e.g., (1, 2), (1, 3), (3, 4), (3, 10), (3, 8), (5, 6), (7, 8) etc.

These numbers are also called as relatively prime numbers.

**Note:**

(a) Two distinct prime numbers are always co-prime but converse need not be true.

(b) Consecutive numbers are always co-prime numbers.

**Twin Prime Numbers:**

If the difference between two prime numbers is two, then the numbers are called as twin prime numbers. e.g., {3, 5}, {5, 7}, {11, 13}, {17, 19}, {29, 31}.