We look at the division of 549531 by 81 
The aim is to understand the frequency of 81 in 549531.

Let's proceed to step 1:
5 divided by 81 is 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Include the next digit (4) from the dividend after 5, then repeat: 54 / 81

Going ahead to step 2:
81 can be fit into 54 0 times, resulting in a remainder of 54.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 54 after subtracting 0 from 54.
Fetch the next digit (9) from the dividend, attach it to 54 and continue: 549 / 81

Let's proceed to step 3:
549 divided by 81 is 6 with a remainder of 63.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
The remainder is 63 after subtracting 486 from 549.
Grab the next digit (5) from the dividend, add it to 63, then carry on: 635 / 81

Moving on to step 4:
81 can be fit into 635 7 times, resulting in a remainder of 68.
Put 7 as the next digit of the answer. 
Result so far: 67.0
Subtract 567 from 635 to get 68.
Take the next digit (3) from the dividend and append it to 68, then repeat: 683 / 81

Advancing to step 5:
The number 81 fits into 683 8 times, leaving a remainder of 35.
Use 8 as the next digit of our solution. 
Result so far: 678.0
Deduct 648 from 683 and we're left with 35.
Append the next digit (1) from the dividend to 35 and continue with: 351 / 81

Moving on to step 6:
81 can be fit into 351 4 times, resulting in a remainder of 27.
Put 4 as the next digit of the answer. 
Result so far: 6784.0
If we subtract 324 from 351, we get 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Moving on to step 7:
81 goes into 270 3 times with a remainder of 27.
The next digit of our result is 3. 
Result so far: 6784.3
The remainder is 27 after subtracting 243 from 270.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Step 8:
81 can be fit into 270 3 times, resulting in a remainder of 27.
The number 3 becomes the next digit in our result. 
Result so far: 6784.33
Subtract 243 from 270 to get 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

The final outcome is 6784.33, with a leftover of 0.027.