We look at the division of 321745 by 81 
The aim is to understand the frequency of 81 in 321745.

Going ahead to step 1:
If we divide 3 by 81, we get 0 and 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.
Take the next digit (2) from the dividend and append it to 3, then repeat: 32 / 81

Advancing to step 2:
32 divided by 81 is 0 with a remainder of 32.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 32 after subtracting 0 from 32.
Grab the next digit (1) from the dividend, add it to 32, then carry on: 321 / 81

On to step 3:
81 goes into 321 3 times with a remainder of 78.
The next digit of our result is 3. 
Result so far: 3.0
Subtracting 243 from 321 leaves us with 78.
Include the next digit (7) from the dividend after 78, then repeat: 787 / 81

Going ahead to step 4:
The number 81 fits into 787 9 times, leaving a remainder of 58.
The next digit of our result is 9. 
Result so far: 39.0
If we take 729 away from 787, we end up with 58.
Grab the next digit (4) from the dividend, add it to 58, then carry on: 584 / 81

Let's proceed to step 5:
The number 81 fits into 584 7 times, leaving a remainder of 17.
Record the quotient 7 as the next digit in the result. 
Result so far: 397.0
Deduct 567 from 584 and we're left with 17.
Append the next digit (5) from the dividend to 17 and continue with: 175 / 81

On to step 6:
The number 81 fits into 175 2 times, leaving a remainder of 13.
Use 2 as the next digit of our solution. 
Result so far: 3972.0
If we subtract 162 from 175, we 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.

On to step 7:
130 divided by 81 is 1 with a remainder of 49.
Write down 1 as next digit of the result. 
Result so far: 3972.1
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.

Let's proceed to step 8:
81 can be fit into 490 6 times, resulting in a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 3972.16
The remainder is 4 after subtracting 486 from 490.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 9:
40 divided by 81 is 0 with a remainder of 40.
Use 0 as the next digit of our solution. 
Result so far: 3972.16
Subtract 0 from 40 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

On to step 10:
81 can be fit into 400 4 times, resulting in a remainder of 76.
Write down 4 as next digit of the result. 
Result so far: 3972.1604
If we subtract 324 from 400, we get 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Step 11:
81 goes into 760 9 times with a remainder of 31.
Use 9 as the next digit of our solution. 
Result so far: 3972.16049
Deduct 729 from 760 and we're left with 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Moving on to step 12:
The number 81 fits into 310 3 times, leaving a remainder of 67.
Put 3 as the next digit of the answer. 
Result so far: 3972.160493
If we take 243 away from 310, we end up with 67.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

Moving on to step 13:
670 divided by 81 is 8 with a remainder of 22.
Write down 8 as next digit of the result. 
Result so far: 3972.1604938
Deduct 648 from 670 and we're left with 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Going ahead to step 14:
81 can be fit into 220 2 times, resulting in a remainder of 58.
Use 2 as the next digit of our solution. 
Result so far: 3972.16049382
Deduct 162 from 220 and we're left with 58.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

After the division, we end up with 3972.16049382 and a remainder of 5.8e-08.