Answer: 6
Step-by-step explanation: To find the greatest common factor for the numbers 18 and 48, make a factor tree for each of the numbers.
18 is 2 · 9 and 9 is 2 · 3.
48 is 2 · 24, 24 is 2 · 12, 12 is 2 · 6, and 6 is 2 · 3.
Our next step is to take a look at those factor trees
and find the factors that are in common to both numbers.
Notice that both numbers have a factor of 3
and both numbers have a factor of 2.
Once you've found the factors that match up,
simply multiply those factors together to get
the greatest common factor for those two numbers.
Since the 3's match up and the 2's match up, the
greatest common factor is 3 × 2 of 6.
Notice that we only multiply by a 3 and a 2 once.
I have attached my factor tree in the image below.
