Answer :
The factors of 68:
1,2,4,17,34,68
1×68
2×34
4×17
------------------------
The factors of 34:
1,2,17,34
1×34
2×17
------------------------
Common factors of 68 and 34:
1 and 34
The GCF is 34
1,2,4,17,34,68
1×68
2×34
4×17
------------------------
The factors of 34:
1,2,17,34
1×34
2×17
------------------------
Common factors of 68 and 34:
1 and 34
The GCF is 34