Answer:
9
Step-by-step explanation:
81= 1,3,9,27,81
72= 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36,72
9 is the most common so GCF will be 9.
See below.
81 - 1,3,9,27,81
72 - 1,2,3,4,6,8,9,12,18,24,36,72
The GCF is 9.
-hope it helps
