We're dividing 618381 by 81 
The aim is to understand the frequency of 81 in 618381.

Going ahead to step 1:
6 divided by 81 is 0 with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Grab the next digit (1) from the dividend, add it to 6, then carry on: 61 / 81

On to step 2:
81 can be fit into 61 0 times, resulting in a remainder of 61.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 61 and we're left with 61.
Grab the next digit (8) from the dividend, add it to 61, then carry on: 618 / 81

Moving on to step 3:
When dividing 618 by 81, we get 7 with a remainder of 51.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
Subtract 567 from 618 to get 51.
Take the next digit (3) from the dividend and append it to 51, then repeat: 513 / 81

Advancing to step 4:
81 can be fit into 513 6 times, resulting in a remainder of 27.
The number 6 becomes the next digit in our result. 
Result so far: 76.0
Subtracting 486 from 513 leaves us with 27.
Take the next digit (8) from the dividend and append it to 27, then repeat: 278 / 81

Going ahead to step 5:
The number 81 fits into 278 3 times, leaving a remainder of 35.
Put 3 as the next digit of the answer. 
Result so far: 763.0
If we take 243 away from 278, we end up with 35.
Include the next digit (1) from the dividend after 35, then repeat: 351 / 81

On to step 6:
The number 81 fits into 351 4 times, leaving a remainder of 27.
Use 4 as the next digit of our solution. 
Result so far: 7634.0
If we take 324 away from 351, we end up with 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:
The number 81 fits into 270 3 times, leaving a remainder of 27.
Write down 3 as next digit of the result. 
Result so far: 7634.3
Deduct 243 from 270 and we're left with 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Advancing to step 8:
81 can be fit into 270 3 times, resulting in a remainder of 27.
The next digit of our result is 3. 
Result so far: 7634.33
If we take 243 away from 270, we end up with 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Our division results in 7634.33 with a remaining 0.027.