# How do you find the GCF of 18, 45mn?

Jan 29, 2017

## 9

#### Explanation:

firstly, write down the factors for each number

$\text{factors of 18: } \left\{1 , 2 , 3 , 6 , 9 , 18\right\}$

$\text{factors of 45"mn} : \left\{1 , 3 , 5 , 9 , 15 , 45 , m , n\right\}$

now pick out the common factors

$\left\{1 , 3 , 9\right\}$

$\therefore G C F = 9$