The GCF is 18.
They are 18, 36, 54, 72, 90, 108, 126, 144 and 162.
18 and 36 do. So do 18 and 54, 36 and 54, 18 and 72, 54 and 72, and an infinite number of other pairs of numbers.
The HCF of 124 and 72 is 4.
The GCF/HCF of 54 and 504 is 18.
54
1, 2, 3, 6, 9, 18, 27, 54 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72 1, 2, 3, 6, 9, 18, 27, 54, 81, 162
18, 36, 54, 72, 90, 108, 126, 144, 162, etc.
18, 36, 54, 72, 90, 108, 126, 144, 162, 180 . . .
18, 36, 54, 72, 90, 108, 126, 144, 162, 180 . . .
The GCF is 18.
3