what is the greatest common LENGTH of 12 and 8 ......????

If you mean the smallest common length:

12, 24, 36, 48
8, 16, 24, 32, 40

What is the smallest number in both lists?

BUT HOW MANY IS IN THEM

What is the smallest number in both lists?

To find the greatest common length of 12 and 8, we need to determine the common factors of these two numbers.

First, let's find the factors of 12:
The factors of 12 are 1, 2, 3, 4, 6, and 12.

Next, let's find the factors of 8:
The factors of 8 are 1, 2, 4, and 8.

To find the greatest common length, we need to identify the greatest factor that these two numbers have in common. From the above list, we see that the greatest common factor of 12 and 8 is 4.

Therefore, the greatest common length of 12 and 8 is 4.