We look at the division of 399193 by 81 
The aim is to understand the frequency of 81 in 399193.

Step 1:
The number 81 fits into 3 0 times, leaving a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 81

Let's proceed to step 2:
When dividing 39 by 81, we get 0 with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 39 to get 39.
Grab the next digit (9) from the dividend, add it to 39, then carry on: 399 / 81

Moving on to step 3:
If we divide 399 by 81, we get 4 and a remainder of 75.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we take 324 away from 399, we end up with 75.
Bring next digit (1) of the dividend behind the 75 and repeat the process: 751 / 81

Moving on to step 4:
81 can be fit into 751 9 times, resulting in a remainder of 22.
Record the quotient 9 as the next digit in the result. 
Result so far: 49.0
The remainder is 22 after subtracting 729 from 751.
Append the next digit (9) from the dividend to 22 and continue with: 229 / 81

Moving on to step 5:
81 can be fit into 229 2 times, resulting in a remainder of 67.
Record the quotient 2 as the next digit in the result. 
Result so far: 492.0
If we take 162 away from 229, we end up with 67.
Grab the next digit (3) from the dividend, add it to 67, then carry on: 673 / 81

Moving on to step 6:
If we divide 673 by 81, we get 8 and a remainder of 25.
Put 8 as the next digit of the answer. 
Result so far: 4928.0
Subtract 648 from 673 to get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Moving on to step 7:
When dividing 250 by 81, we get 3 with a remainder of 7.
Put 3 as the next digit of the answer. 
Result so far: 4928.3
Subtract 243 from 250 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 8:
81 goes into 70 0 times with a remainder of 70.
Record the quotient 0 as the next digit in the result. 
Result so far: 4928.3
If we take 0 away from 70, we end up with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Moving on to step 9:
81 can be fit into 700 8 times, resulting in a remainder of 52.
Put 8 as the next digit of the answer. 
Result so far: 4928.308
Deduct 648 from 700 and we're left with 52.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Let's proceed to step 10:
81 can be fit into 520 6 times, resulting in a remainder of 34.
Use 6 as the next digit of our solution. 
Result so far: 4928.3086
If we take 486 away from 520, we end up with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

On to step 11:
81 goes into 340 4 times with a remainder of 16.
The next digit of our result is 4. 
Result so far: 4928.30864
If we subtract 324 from 340, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 12:
81 goes into 160 1 times with a remainder of 79.
Use 1 as the next digit of our solution. 
Result so far: 4928.308641
Subtract 81 from 160 to get 79.
Since there are no more digits in the dividend, we add a zero to the remainder making it 790, and continue the process.

Moving on to step 13:
If we divide 790 by 81, we get 9 and a remainder of 61.
The next digit of our result is 9. 
Result so far: 4928.3086419
The remainder is 61 after subtracting 729 from 790.
Since there are no more digits in the dividend, we add a zero to the remainder making it 610, and continue the process.

Let's proceed to step 14:
When dividing 610 by 81, we get 7 with a remainder of 43.
The number 7 becomes the next digit in our result. 
Result so far: 4928.30864197
The remainder is 43 after subtracting 567 from 610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

The final outcome is 4928.30864197, with a leftover of 4.3e-08.