We're dividing 399280 by 12 
The aim is to understand the frequency of 12 in 399280.

Moving on to step 1:
If we divide 3 by 12, we get 0 and a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 12

Going ahead to step 2:
12 goes into 39 3 times with a remainder of 3.
Write down 3 as next digit of the result. 
Result so far: 3.0
Subtracting 36 from 39 leaves us with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 12

On to step 3:
When dividing 39 by 12, we get 3 with 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.
Grab the next digit (2) from the dividend, add it to 3, then carry on: 32 / 12

Advancing to step 4:
If we divide 32 by 12, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 332.0
Subtracting 24 from 32 leaves us with 8.
Take the next digit (8) from the dividend and append it to 8, then repeat: 88 / 12

Step 5:
When dividing 88 by 12, we get 7 with a remainder of 4.
The next digit of our result is 7. 
Result so far: 3327.0
Subtract 84 from 88 to get 4.
Bring next digit (0) of the dividend behind the 4 and repeat the process: 40 / 12

Going ahead to step 6:
40 divided by 12 is 3 with a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 33273.0
Subtracting 36 from 40 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 7:
12 can be fit into 40 3 times, resulting in a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 33273.3
Deduct 36 from 40 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 8:
The number 12 fits into 40 3 times, leaving a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 33273.33
If we subtract 36 from 40, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

In conclusion, the division gives 33273.33 with a balance of 0.004.