The GCF is 2.
The factors of 42 are 1, 2, 3, 6, 7, 14, 21 and 42. The factors of 38 are 1, 2, 19 and 38. 2 is the greatest factor which divides both 38 and 42. So, the GCF of 42 and 38 is 2.
The GCF of 38 and 76 is 38. Since 38 is a factor of 76, it is automatically the GCF.
The GCF is 2.
The GCF is 4.
The GCF is 2.
The GCF is 2.
The GCF is 22.
The GCF is 2.
The GCF is 38.
The GCF is 1.
The GCF is 2.