Question

What is the GCF for 54, 72?

Answer 1

Greatest Common Factor is `18`

Explanation:

Factors of `54` are `{1,2,3,6,9,18,27,54}`

Factors of `72` are `{1,2,3,4,6,8,9,12,18,24,36,72}`

Hence common factors are `{1,2,3,6,9,18}`

and Greatest Common Factor is `18`

Answer 2

The GCF of `72` and `54` is `18`.

Explanation:

One way of finding the GCF of two numbers goes as follows:

• Divide the larger number by the smaller to give a quotient and remainder.

• If the remainder is `0` then the smaller number is the GCF.

• Otherwise repeat with the smaller number and the remainder.

In our example, we find:

`72/54 = 1` with remainder `18`

`54/18 = 3` with remainder `0`

So the GCF is `18`.

Answer 3

18

Explanation:

Find the prime factors of each number and see how many factors are shared by both numbers.

`" "54=2xxcolor(white)(2xx2)xx3xx3xx3`
`" "72=2xx2xx2xx3xx3`
GCF=`" " 2color(white)(2xx2xx)xx3xx3" "=18`