Find the GCF 210 , 90

$210$ , $90$

Find the common factors for the numerical part:

$210, 90$

The factors for $210$ are $1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210$ .

The factors for $210$ are all numbers between $1$ and $210$ , which divide $210$ evenly.

Check numbers between $1$ and $210$

Find the factor pairs of $210$ where $x \cdot y = 210$ .

$\begin{array}{c} x & y \\ 1 & 210 \\ 2 & 105 \\ 3 & 70 \\ 5 & 42 \\ 6 & 35 \\ 7 & 30 \\ 10 & 21 \\ 14 & 15 \end{array}$

List the factors for $210$ .

$1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210$

The factors for $90$ are $1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90$ .

The factors for $90$ are all numbers between $1$ and $90$ , which divide $90$ evenly.

Check numbers between $1$ and $90$

Find the factor pairs of $90$ where $x \cdot y = 90$ .

$\begin{array}{c} x & y \\ 1 & 90 \\ 2 & 45 \\ 3 & 30 \\ 5 & 18 \\ 6 & 15 \\ 9 & 10 \end{array}$

List the factors for $90$ .

$1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90$

List all the factors for $210, 90$ to find the common factors.

$210$ : $1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210$

$90$ : $1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90$

The common factors for $210, 90$ are $1, 2, 3, 5, 6, 10, 15, 30$ .

$1, 2, 3, 5, 6, 10, 15, 30$

The GCF (HCF) of the numerical factors $1, 2, 3, 5, 6, 10, 15, 30$ is $30$ .

$30$