To find the greatest common factor of 40 and 27, we can first start by making a list of factors for each number.
The factors of 27 are: 1, 3, 9, 27
The factors of 40 are: 1, 2, 4, 5, 8, 10, 20, 40
When looking at these numbers, we can see that 1 is the greatest common factor of both 40 and 27.