We look at the division of 837699 by 81 
The aim is to understand the frequency of 81 in 837699.

Going ahead to step 1:
When dividing 8 by 81, we get 0 with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Take the next digit (3) from the dividend and append it to 8, then repeat: 83 / 81

Going ahead to step 2:
The number 81 fits into 83 1 times, leaving a remainder of 2.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Deduct 81 from 83 and we're left with 2.
Fetch the next digit (7) from the dividend, attach it to 2 and continue: 27 / 81

Going ahead to step 3:
The number 81 fits into 27 0 times, leaving a remainder of 27.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
Subtracting 0 from 27 leaves us with 27.
Append the next digit (6) from the dividend to 27 and continue with: 276 / 81

Going ahead to step 4:
81 can be fit into 276 3 times, resulting in a remainder of 33.
The number 3 becomes the next digit in our result. 
Result so far: 103.0
Deduct 243 from 276 and we're left with 33.
Take the next digit (9) from the dividend and append it to 33, then repeat: 339 / 81

Going ahead to step 5:
81 can be fit into 339 4 times, resulting in a remainder of 15.
Put 4 as the next digit of the answer. 
Result so far: 1034.0
If we take 324 away from 339, we end up with 15.
Take the next digit (9) from the dividend and append it to 15, then repeat: 159 / 81

Moving on to step 6:
If we divide 159 by 81, we get 1 and a remainder of 78.
Put 1 as the next digit of the answer. 
Result so far: 10341.0
The remainder is 78 after subtracting 81 from 159.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Going ahead to step 7:
If we divide 780 by 81, we get 9 and a remainder of 51.
Use 9 as the next digit of our solution. 
Result so far: 10341.9
Subtracting 729 from 780 leaves us with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Let's proceed to step 8:
81 goes into 510 6 times with a remainder of 24.
Put 6 as the next digit of the answer. 
Result so far: 10341.96
If we take 486 away from 510, we end up with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Going ahead to step 9:
When dividing 240 by 81, we get 2 with a remainder of 78.
Put 2 as the next digit of the answer. 
Result so far: 10341.962
If we subtract 162 from 240, we get 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Moving on to step 10:
780 divided by 81 is 9 with a remainder of 51.
Write down 9 as next digit of the result. 
Result so far: 10341.9629
Subtracting 729 from 780 leaves us with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

On to step 11:
The number 81 fits into 510 6 times, leaving a remainder of 24.
Write down 6 as next digit of the result. 
Result so far: 10341.96296
If we take 486 away from 510, we end up with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Moving on to step 12:
The number 81 fits into 240 2 times, leaving a remainder of 78.
The next digit of our result is 2. 
Result so far: 10341.962962
Subtract 162 from 240 to get 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Advancing to step 13:
The number 81 fits into 780 9 times, leaving a remainder of 51.
Write down 9 as next digit of the result. 
Result so far: 10341.9629629
If we take 729 away from 780, we end up with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Step 14:
81 goes into 510 6 times with a remainder of 24.
Put 6 as the next digit of the answer. 
Result so far: 10341.96296296
The remainder is 24 after subtracting 486 from 510.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

After the division, we end up with 10341.96296296 and a remainder of 2.4e-08.