Greatest Common Factors (GCF) can help you in real life problems with fractions and measuring things. Below is a real life example.
Let's say you want to send cookies into one of two classes and want to make sure you have an even number per student. You know that one class has 8 students and the other has 10 students. How many cookies do you make?
Answer: All you have to do is figure out the biggest number that goes into each number equally (division). In this case the answer would be 2.
If i helped please comment below 
And i hope i helped you!