The greatest factor of an even number will always be that number divided by
two. (We don't count the number itself since that wouldn't be very
interesting or useful.)
FACTORS of 20: 1, 2, 4, 5, 10, 20.
GREATEST FACTOR OF 20: 10.
20 / 2 = 10
Here's another example using a different even number.
FACTORS of 32: 1, 2, 4, 8, 16, 32.
GREATEST FACTOR OF 32: 16.
32 / 2 = 16
In the next practice exercise you will be asked to identify the largest
factor of each number.