587640 ÷ 81 
The aim is to understand the frequency of 81 in 587640.

Advancing to step 1:
5 divided by 81 is 0 with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Append the next digit (8) from the dividend to 5 and continue with: 58 / 81

Going ahead to step 2:
The number 81 fits into 58 0 times, leaving a remainder of 58.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 58 after subtracting 0 from 58.
Take the next digit (7) from the dividend and append it to 58, then repeat: 587 / 81

Moving on to step 3:
If we divide 587 by 81, we get 7 and a remainder of 20.
Put 7 as the next digit of the answer. 
Result so far: 7.0
Deduct 567 from 587 and we're left with 20.
Grab the next digit (6) from the dividend, add it to 20, then carry on: 206 / 81

Moving on to step 4:
81 goes into 206 2 times with a remainder of 44.
The next digit of our result is 2. 
Result so far: 72.0
Subtracting 162 from 206 leaves us with 44.
Fetch the next digit (4) from the dividend, attach it to 44 and continue: 444 / 81

Step 5:
444 divided by 81 is 5 with a remainder of 39.
Put 5 as the next digit of the answer. 
Result so far: 725.0
Subtracting 405 from 444 leaves us with 39.
Append the next digit (0) from the dividend to 39 and continue with: 390 / 81

On to step 6:
The number 81 fits into 390 4 times, leaving a remainder of 66.
Use 4 as the next digit of our solution. 
Result so far: 7254.0
The remainder is 66 after subtracting 324 from 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Moving on to step 7:
If we divide 660 by 81, we get 8 and a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 7254.8
Deduct 648 from 660 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 8:
81 can be fit into 120 1 times, resulting in a remainder of 39.
Use 1 as the next digit of our solution. 
Result so far: 7254.81
If we subtract 81 from 120, we get 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

On to step 9:
When dividing 390 by 81, we get 4 with a remainder of 66.
Use 4 as the next digit of our solution. 
Result so far: 7254.814
Subtract 324 from 390 to get 66.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Let's proceed to step 10:
When dividing 660 by 81, we get 8 with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 7254.8148
If we subtract 648 from 660, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 11:
If we divide 120 by 81, we get 1 and a remainder of 39.
Write down 1 as next digit of the result. 
Result so far: 7254.81481
If we subtract 81 from 120, we get 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

Going ahead to step 12:
81 goes into 390 4 times with a remainder of 66.
The number 4 becomes the next digit in our result. 
Result so far: 7254.814814
The remainder is 66 after subtracting 324 from 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Going ahead to step 13:
The number 81 fits into 660 8 times, leaving a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 7254.8148148
If we subtract 648 from 660, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 14:
When dividing 120 by 81, we get 1 with a remainder of 39.
The number 1 becomes the next digit in our result. 
Result so far: 7254.81481481
If we take 81 away from 120, we end up with 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

The final result is 7254.81481481 with a remainder of 3.9e-08.