Answer: 6
Explanation:
Well gcf stands for Greatest Common Factor, which basically means 'what is the biggest number that these two numbers can be divided into?'
To start you list all the common factors of 24 and then 30.
24: 1,2,3,4,6,8,12,24
30: 1,2,3,5,6,10,15,30
List the same factors of them both:
1,2,3,6
Now find the biggest one which in this case is 6. 6 is your gcf.