We're dividing 872599 by 81 
The aim is to understand the frequency of 81 in 872599.

Step 1:
81 can be fit into 8 0 times, resulting in a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Take the next digit (7) from the dividend and append it to 8, then repeat: 87 / 81

On to step 2:
81 goes into 87 1 times with a remainder of 6.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we subtract 81 from 87, we get 6.
Fetch the next digit (2) from the dividend, attach it to 6 and continue: 62 / 81

On to step 3:
If we divide 62 by 81, we get 0 and a remainder of 62.
Write down 0 as next digit of the result. 
Result so far: 10.0
Subtracting 0 from 62 leaves us with 62.
Include the next digit (5) from the dividend after 62, then repeat: 625 / 81

Advancing to step 4:
The number 81 fits into 625 7 times, leaving a remainder of 58.
Write down 7 as next digit of the result. 
Result so far: 107.0
The remainder is 58 after subtracting 567 from 625.
Include the next digit (9) from the dividend after 58, then repeat: 589 / 81

Advancing to step 5:
589 divided by 81 is 7 with a remainder of 22.
Record the quotient 7 as the next digit in the result. 
Result so far: 1077.0
Deduct 567 from 589 and we're left with 22.
Include the next digit (9) from the dividend after 22, then repeat: 229 / 81

Step 6:
229 divided by 81 is 2 with a remainder of 67.
Record the quotient 2 as the next digit in the result. 
Result so far: 10772.0
Subtract 162 from 229 to get 67.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

Going ahead to step 7:
670 divided by 81 is 8 with a remainder of 22.
The number 8 becomes the next digit in our result. 
Result so far: 10772.8
Subtract 648 from 670 to get 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Advancing to step 8:
220 divided by 81 is 2 with a remainder of 58.
Write down 2 as next digit of the result. 
Result so far: 10772.82
The remainder is 58 after subtracting 162 from 220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Moving on to step 9:
580 divided by 81 is 7 with a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 10772.827
Subtract 567 from 580 to get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 10:
When dividing 130 by 81, we get 1 with a remainder of 49.
Record the quotient 1 as the next digit in the result. 
Result so far: 10772.8271
Subtract 81 from 130 to get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

Advancing to step 11:
When dividing 490 by 81, we get 6 with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 10772.82716
Deduct 486 from 490 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.

Going ahead to step 12:
When dividing 40 by 81, we get 0 with a remainder of 40.
Use 0 as the next digit of our solution. 
Result so far: 10772.82716
Subtracting 0 from 40 leaves us with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Going ahead to step 13:
The number 81 fits into 400 4 times, leaving a remainder of 76.
Record the quotient 4 as the next digit in the result. 
Result so far: 10772.8271604
Deduct 324 from 400 and we're left with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

On to step 14:
When dividing 760 by 81, we get 9 with a remainder of 31.
The number 9 becomes the next digit in our result. 
Result so far: 10772.82716049
If we subtract 729 from 760, we get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Our division results in 10772.82716049 with a remaining 3.1e-08.