658164 ÷ 81 
The aim is to understand the frequency of 81 in 658164.

Step 1:
If we divide 6 by 81, we get 0 and a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Include the next digit (5) from the dividend after 6, then repeat: 65 / 81

Going ahead to step 2:
When dividing 65 by 81, we get 0 with a remainder of 65.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 65, we end up with 65.
Take the next digit (8) from the dividend and append it to 65, then repeat: 658 / 81

Let's proceed to step 3:
81 goes into 658 8 times with a remainder of 10.
Use 8 as the next digit of our solution. 
Result so far: 8.0
The remainder is 10 after subtracting 648 from 658.
Take the next digit (1) from the dividend and append it to 10, then repeat: 101 / 81

Step 4:
If we divide 101 by 81, we get 1 and a remainder of 20.
Record the quotient 1 as the next digit in the result. 
Result so far: 81.0
If we take 81 away from 101, we end up with 20.
Take the next digit (6) from the dividend and append it to 20, then repeat: 206 / 81

Step 5:
206 divided by 81 is 2 with a remainder of 44.
Put 2 as the next digit of the answer. 
Result so far: 812.0
Subtract 162 from 206 to get 44.
Fetch the next digit (4) from the dividend, attach it to 44 and continue: 444 / 81

Let's proceed to step 6:
444 divided by 81 is 5 with a remainder of 39.
Put 5 as the next digit of the answer. 
Result so far: 8125.0
The remainder is 39 after subtracting 405 from 444.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

Moving on to step 7:
If we divide 390 by 81, we get 4 and a remainder of 66.
Record the quotient 4 as the next digit in the result. 
Result so far: 8125.4
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.

On to step 8:
If we divide 660 by 81, we get 8 and a remainder of 12.
The next digit of our result is 8. 
Result so far: 8125.48
The remainder is 12 after subtracting 648 from 660.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 9:
The number 81 fits into 120 1 times, leaving a remainder of 39.
The number 1 becomes the next digit in our result. 
Result so far: 8125.481
The remainder is 39 after subtracting 81 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

Advancing to step 10:
81 can be fit into 390 4 times, resulting in a remainder of 66.
The next digit of our result is 4. 
Result so far: 8125.4814
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.

Advancing to step 11:
When dividing 660 by 81, we get 8 with a remainder of 12.
The next digit of our result is 8. 
Result so far: 8125.48148
Subtract 648 from 660 to 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 12:
81 can be fit into 120 1 times, resulting in a remainder of 39.
Write down 1 as next digit of the result. 
Result so far: 8125.481481
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.

Moving on to step 13:
The number 81 fits into 390 4 times, leaving a remainder of 66.
Record the quotient 4 as the next digit in the result. 
Result so far: 8125.4814814
If we take 324 away from 390, we end up with 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 14:
81 goes into 660 8 times with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 8125.48148148
The remainder is 12 after subtracting 648 from 660.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

The final outcome is 8125.48148148, with a leftover of 1.2e-08.