# How do you find the GCF of 20 and 30?

##### 1 Answer

Jan 11, 2017

#### Answer:

The preferred technique is to factor each number then multiply all common factors together to find the greatest common factor.

#### Explanation:

First factor 20 down to its prime factors.

Second factor 30 down to its prime factors

The common factors are 2 and 5.

The greatest common factor is

There are shortcuts that often work however

20 can be easily factored into

30 can be easily factored into

10 can then be easily be seen as the greatest common factor.