Question

How do you find the GCF of `10ab, 25a`?

Answer 1

`5a`

Explanation:

To find the GCF, look for the factor that both terms have in common
This one is `5a`

Answer 2

`HCF = 5a`

Explanation:

Write each term as the product of its prime factors:
Identify which factors are common to both

`" "10ab = 2xxcolor(blue)(5)color(white)(xxx)xxcolor(blue)(a)xxb`
`" "25a = ul(color(white)(xx.x)color(blue)(5) xx 5xxcolor(blue)(a))`
`HCF = color(white)(xxxxx)color(blue)(5)color(white)(xxx)xxcolor(blue)(a) = 5a`

This method is very useful if you are working with several numbers, especially of they are large and unfamiliar.