For A the great common factor is 3 because if you were to do 3,6,9 and then 36- 3,6,9,12,15,18,21,24,27,30,36 the greatest common factor (GCF) would be 3.
For B the greatest common factor is 28 because if you were to do 7,14,21,28, twenty-eight is the highest number possible and for 42 you would do 7,14,21,28,35,42 the highest number possible for them to match would be 28 so the answer is 28 for B
