Find the GCF 20 , 36

$20$ , $36$

Step 1

Find the common factors for the numerical part:

$20, 36$

Step 2

The factors for $20$ are $1, 2, 4, 5, 10, 20$ .

The factors for $20$ are all numbers between $1$ and $20$ , which divide $20$ evenly.

Check numbers between $1$ and $20$

Find the factor pairs of $20$ where $x \cdot y = 20$ .

$\begin{array}{c} x & y \\ 1 & 20 \\ 2 & 10 \\ 4 & 5 \end{array}$

List the factors for $20$ .

$1, 2, 4, 5, 10, 20$

Step 3

The factors for $36$ are $1, 2, 3, 4, 6, 9, 12, 18, 36$ .

The factors for $36$ are all numbers between $1$ and $36$ , which divide $36$ evenly.

Check numbers between $1$ and $36$

Find the factor pairs of $36$ where $x \cdot y = 36$ .

$\begin{array}{c} x & y \\ 1 & 36 \\ 2 & 18 \\ 3 & 12 \\ 4 & 9 \\ 6 & 6 \end{array}$

List the factors for $36$ .

$1, 2, 3, 4, 6, 9, 12, 18, 36$

Step 4

List all the factors for $20, 36$ to find the common factors.

$20$ : $1, 2, 4, 5, 10, 20$

$36$ : $1, 2, 3, 4, 6, 9, 12, 18, 36$

Step 5

The common factors for $20, 36$ are $1, 2, 4$ .

$1, 2, 4$

Step 6

The GCF (HCF) of the numerical factors $1, 2, 4$ is $4$ .

$4$