864551 ÷ 81 
The aim is to understand the frequency of 81 in 864551.

Let's proceed to step 1:
When dividing 8 by 81, we get 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Include the next digit (6) from the dividend after 8, then repeat: 86 / 81

On to step 2:
The number 81 fits into 86 1 times, leaving a remainder of 5.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 81 from 86 leaves us with 5.
Include the next digit (4) from the dividend after 5, then repeat: 54 / 81

Going ahead to step 3:
81 goes into 54 0 times with a remainder of 54.
Record the quotient 0 as the next digit in the result. 
Result so far: 10.0
If we take 0 away from 54, we end up with 54.
Include the next digit (5) from the dividend after 54, then repeat: 545 / 81

Going ahead to step 4:
81 goes into 545 6 times with a remainder of 59.
The next digit of our result is 6. 
Result so far: 106.0
If we take 486 away from 545, we end up with 59.
Append the next digit (5) from the dividend to 59 and continue with: 595 / 81

On to step 5:
The number 81 fits into 595 7 times, leaving a remainder of 28.
Put 7 as the next digit of the answer. 
Result so far: 1067.0
If we subtract 567 from 595, we get 28.
Fetch the next digit (1) from the dividend, attach it to 28 and continue: 281 / 81

Going ahead to step 6:
When dividing 281 by 81, we get 3 with a remainder of 38.
Write down 3 as next digit of the result. 
Result so far: 10673.0
Subtract 243 from 281 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Let's proceed to step 7:
When dividing 380 by 81, we get 4 with a remainder of 56.
Write down 4 as next digit of the result. 
Result so far: 10673.4
The remainder is 56 after subtracting 324 from 380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Let's proceed to step 8:
81 can be fit into 560 6 times, resulting in a remainder of 74.
The next digit of our result is 6. 
Result so far: 10673.46
If we take 486 away from 560, we end up with 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

On to step 9:
When dividing 740 by 81, we get 9 with a remainder of 11.
Use 9 as the next digit of our solution. 
Result so far: 10673.469
If we subtract 729 from 740, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 10:
81 can be fit into 110 1 times, resulting in a remainder of 29.
Write down 1 as next digit of the result. 
Result so far: 10673.4691
If we take 81 away from 110, we end up with 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

Moving on to step 11:
When dividing 290 by 81, we get 3 with a remainder of 47.
Write down 3 as next digit of the result. 
Result so far: 10673.46913
Subtract 243 from 290 to get 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Step 12:
If we divide 470 by 81, we get 5 and a remainder of 65.
Record the quotient 5 as the next digit in the result. 
Result so far: 10673.469135
If we subtract 405 from 470, we get 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

Let's proceed to step 13:
If we divide 650 by 81, we get 8 and a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 10673.4691358
If we subtract 648 from 650, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 14:
81 can be fit into 20 0 times, resulting in a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 10673.4691358
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The final result is 10673.4691358 with a remainder of 2e-08.