Answer: 3
Step-by-step explanation: To find the (GCF) or greatest common factor of 3 and 6, begin by finding all of the factors of 3.
Since 3 ÷ 1 is 3, this means that 1 and 3 are factors.
Since 3 ÷ 2 doesn't divide evenly and 3 ÷ 3 gives us repeat factors, we know that the factors of 3 are just 1 and 3.
Next, we find all of the factors of 6.
6 ÷ 1 is 6 so 1 and 6 are factors.
6 ÷ 2 is 3 which means that 2 and 3 are factors.
6 ÷ 3 is 2, but 2 and 3 are repeat factors so we can stop here.
This means that the factors of 6 are 1, 2, 3, and 6.
Now we look for the largest factor that is shared by the two lists which is 3.
Therefore, the greatest common factor of 3 and 6 is 3.