Question

Define: Coprime Number

Answer 1

Coprime numbers are those numbers that have only one common factor, namely 1. That means a pair of numbers they have their highest common factor(HCF) as 1.

Example 1: 18 and 19

• The factors of 18 are 1, 2, 3, 6, 9 and 18.
• The factors of 19 are 1, and 19.

Here 18 and 19 have only one common factor that is 1. Hence, 18 and 19 are co-prime numbers.

Example 2: 21 and 27

• The factors of 21 are 1, 3, 7, and 21.
• The factors of 27 are 1, 3, 9, and 27.

Here 21 and 27 have two common factors; they are 1 and 3. HCF is 3 and they are not co-prime.