We're dividing 399641 by 18 
The aim is to understand the frequency of 18 in 399641.

Step 1:
18 can be fit into 3 0 times, resulting in a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 18

Moving on to step 2:
39 divided by 18 is 2 with a remainder of 3.
Write down 2 as next digit of the result. 
Result so far: 2.0
If we take 36 away from 39, we end up with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 18

Advancing to step 3:
18 can be fit into 39 2 times, resulting in a remainder of 3.
Use 2 as the next digit of our solution. 
Result so far: 22.0
If we take 36 away from 39, we end up with 3.
Take the next digit (6) from the dividend and append it to 3, then repeat: 36 / 18

Advancing to step 4:
If we divide 36 by 18, we get 2 and a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 222.0
If we subtract 36 from 36, we get 0.
Take the next digit (4) from the dividend and append it to 0, then repeat: 4 / 18

Going ahead to step 5:
If we divide 4 by 18, we get 0 and a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 2220.0
If we subtract 0 from 4, we get 4.
Grab the next digit (1) from the dividend, add it to 4, then carry on: 41 / 18

Let's proceed to step 6:
The number 18 fits into 41 2 times, leaving a remainder of 5.
Use 2 as the next digit of our solution. 
Result so far: 22202.0
Subtract 36 from 41 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 7:
18 goes into 50 2 times with a remainder of 14.
Use 2 as the next digit of our solution. 
Result so far: 22202.2
Deduct 36 from 50 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 8:
When dividing 140 by 18, we get 7 with a remainder of 14.
Record the quotient 7 as the next digit in the result. 
Result so far: 22202.27
Deduct 126 from 140 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Let's proceed to step 9:
When dividing 140 by 18, we get 7 with a remainder of 14.
The next digit of our result is 7. 
Result so far: 22202.277
If we subtract 126 from 140, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

In conclusion, the division gives 22202.277 with a balance of 0.0014.