Answer:
3
Step-by-step explanation:
The GCF of 6 and 9 is 3. To calculate the GCF of 6 and 9, we need to factor each number (factors of 6 = 1, 2, 3, 6; factors of 9 = 1, 3, 9) and choose the greatest factor that exactly divides both 6 and 9, i.e., 3.