Let's divide 39972 by 12
The aim is to understand the frequency of 12 in 39972.

Going ahead to step 1:
3 divided by 12 is 0 with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 12

Moving on to step 2:
The number 12 fits into 39 3 times, leaving a remainder of 3.
Write down 3 as next digit of the result. 
Result so far: 3.0
If we take 36 away from 39, we end up with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 12

Moving on to step 3:
12 can be fit into 39 3 times, resulting in a remainder of 3.
The next digit of our result is 3. 
Result so far: 33.0
Subtracting 36 from 39 leaves us with 3.
Bring next digit (7) of the dividend behind the 3 and repeat the process: 37 / 12

Let's proceed to step 4:
12 goes into 37 3 times with a remainder of 1.
Use 3 as the next digit of our solution. 
Result so far: 333.0
If we take 36 away from 37, we end up with 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 12

Moving on to step 5:
12 divided by 12 is 1 with a remainder of 0.
Put 1 as the next digit of the answer. 
Result so far: 3331.0
The remainder is 0 after subtracting 12 from 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 6:
If we divide 0 by 12, we get 0 and a remainder of 0.
The next digit of our result is 0. 
Result so far: 3331.0
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 7:
The number 12 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 3331.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 3331.0, and the remainder is 0.0.