We look at the division of 391384 by 81 
The aim is to understand the frequency of 81 in 391384.

Advancing to step 1:
81 can be fit into 3 0 times, resulting in a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 81

Step 2:
The number 81 fits into 39 0 times, leaving a remainder of 39.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 39 after subtracting 0 from 39.
Bring next digit (1) of the dividend behind the 39 and repeat the process: 391 / 81

Step 3:
The number 81 fits into 391 4 times, leaving a remainder of 67.
Use 4 as the next digit of our solution. 
Result so far: 4.0
The remainder is 67 after subtracting 324 from 391.
Take the next digit (3) from the dividend and append it to 67, then repeat: 673 / 81

Advancing to step 4:
If we divide 673 by 81, we get 8 and a remainder of 25.
Write down 8 as next digit of the result. 
Result so far: 48.0
Subtract 648 from 673 to get 25.
Include the next digit (8) from the dividend after 25, then repeat: 258 / 81

Advancing to step 5:
If we divide 258 by 81, we get 3 and a remainder of 15.
Write down 3 as next digit of the result. 
Result so far: 483.0
Deduct 243 from 258 and we're left with 15.
Grab the next digit (4) from the dividend, add it to 15, then carry on: 154 / 81

Moving on to step 6:
154 divided by 81 is 1 with a remainder of 73.
Put 1 as the next digit of the answer. 
Result so far: 4831.0
The remainder is 73 after subtracting 81 from 154.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Moving on to step 7:
81 can be fit into 730 9 times, resulting in a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 4831.9
If we take 729 away from 730, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 8:
81 can be fit into 10 0 times, resulting in a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 4831.9
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 9:
When dividing 100 by 81, we get 1 with a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 4831.901
Deduct 81 from 100 and we're left with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 10:
81 can be fit into 190 2 times, resulting in a remainder of 28.
Write down 2 as next digit of the result. 
Result so far: 4831.9012
The remainder is 28 after subtracting 162 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Moving on to step 11:
If we divide 280 by 81, we get 3 and a remainder of 37.
Record the quotient 3 as the next digit in the result. 
Result so far: 4831.90123
Deduct 243 from 280 and we're left with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Going ahead to step 12:
The number 81 fits into 370 4 times, leaving a remainder of 46.
Use 4 as the next digit of our solution. 
Result so far: 4831.901234
The remainder is 46 after subtracting 324 from 370.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Advancing to step 13:
If we divide 460 by 81, we get 5 and a remainder of 55.
Write down 5 as next digit of the result. 
Result so far: 4831.9012345
Subtract 405 from 460 to get 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

Advancing to step 14:
If we divide 550 by 81, we get 6 and a remainder of 64.
Use 6 as the next digit of our solution. 
Result so far: 4831.90123456
Subtract 486 from 550 to get 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

The final outcome is 4831.90123456, with a leftover of 6.4e-08.