689817 ÷ 81 
The aim is to understand the frequency of 81 in 689817.

Moving on to step 1:
6 divided by 81 is 0 with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Fetch the next digit (8) from the dividend, attach it to 6 and continue: 68 / 81

On to step 2:
If we divide 68 by 81, we get 0 and a remainder of 68.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 68 after subtracting 0 from 68.
Take the next digit (9) from the dividend and append it to 68, then repeat: 689 / 81

Advancing to step 3:
When dividing 689 by 81, we get 8 with a remainder of 41.
Put 8 as the next digit of the answer. 
Result so far: 8.0
Subtracting 648 from 689 leaves us with 41.
Append the next digit (8) from the dividend to 41 and continue with: 418 / 81

Step 4:
If we divide 418 by 81, we get 5 and a remainder of 13.
The next digit of our result is 5. 
Result so far: 85.0
If we subtract 405 from 418, we get 13.
Grab the next digit (1) from the dividend, add it to 13, then carry on: 131 / 81

Moving on to step 5:
When dividing 131 by 81, we get 1 with a remainder of 50.
Put 1 as the next digit of the answer. 
Result so far: 851.0
If we subtract 81 from 131, we get 50.
Append the next digit (7) from the dividend to 50 and continue with: 507 / 81

Advancing to step 6:
81 can be fit into 507 6 times, resulting in a remainder of 21.
The number 6 becomes the next digit in our result. 
Result so far: 8516.0
Subtracting 486 from 507 leaves us with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

On to step 7:
The number 81 fits into 210 2 times, leaving a remainder of 48.
The next digit of our result is 2. 
Result so far: 8516.2
If we subtract 162 from 210, we get 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Going ahead to step 8:
480 divided by 81 is 5 with a remainder of 75.
Use 5 as the next digit of our solution. 
Result so far: 8516.25
Subtract 405 from 480 to get 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Let's proceed to step 9:
If we divide 750 by 81, we get 9 and a remainder of 21.
Record the quotient 9 as the next digit in the result. 
Result so far: 8516.259
If we subtract 729 from 750, we get 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Going ahead to step 10:
81 goes into 210 2 times with a remainder of 48.
The next digit of our result is 2. 
Result so far: 8516.2592
The remainder is 48 after subtracting 162 from 210.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Going ahead to step 11:
480 divided by 81 is 5 with a remainder of 75.
Write down 5 as next digit of the result. 
Result so far: 8516.25925
Subtract 405 from 480 to get 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Moving on to step 12:
81 goes into 750 9 times with a remainder of 21.
Record the quotient 9 as the next digit in the result. 
Result so far: 8516.259259
If we take 729 away from 750, we end up with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Let's proceed to step 13:
If we divide 210 by 81, we get 2 and a remainder of 48.
Put 2 as the next digit of the answer. 
Result so far: 8516.2592592
The remainder is 48 after subtracting 162 from 210.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

On to step 14:
If we divide 480 by 81, we get 5 and a remainder of 75.
Record the quotient 5 as the next digit in the result. 
Result so far: 8516.25925925
Deduct 405 from 480 and we're left with 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Our division results in 8516.25925925 with a remaining 7.5e-08.