Answer:
1. 12,18, 12/6 = 2 and 18/6 = 3, so 6 is your GCF
2. 10,35, 10/5 = 2 and 35/5 = 7, so if it can't reduce anymore with the same GCF then 5 is your GCF.
3. 8,30, 8/2 = 4 and 30/2 = 15 which can't be reduced anymore which leaves 2 as the GCF
4. 16,24, 16/8 = 2 and 24/8 = 3 which makes 8 your GCF
5. 28,49, 28/7 = 4 and 49/7 = 7, so if you think about it there is no bigger number that can go into both of these numbers except 7. 7 is your GCF
6. 27,63, 27/9 = 3 and 63/9 = 7, your GCF is 9
7. 30,45, 30/5 = 6 and 45/5 = 9, your GCF is 5 because no other number can go into these numbers that is bigger than 5.
8. 48,72, 48/12 = 4 and 72/12 = 6, I tried to go bigger but I got a decimal so it makes the GCF 12.
Step-by-step explanation:
First you are going to want to find a number that goes into both of the chosen numbers.
Second if you can find a bigger number that goes into your chosen number
Third if you can't find a bigger number than you have found your GCF