398310 ÷ 81 
The aim is to understand the frequency of 81 in 398310.

On to step 1:
81 goes into 3 0 times with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 81

Step 2:
If we divide 39 by 81, we get 0 and a remainder of 39.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 39 leaves us with 39.
Take the next digit (8) from the dividend and append it to 39, then repeat: 398 / 81

Going ahead to step 3:
The number 81 fits into 398 4 times, leaving a remainder of 74.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Subtracting 324 from 398 leaves us with 74.
Append the next digit (3) from the dividend to 74 and continue with: 743 / 81

Moving on to step 4:
If we divide 743 by 81, we get 9 and a remainder of 14.
Record the quotient 9 as the next digit in the result. 
Result so far: 49.0
If we subtract 729 from 743, we get 14.
Fetch the next digit (1) from the dividend, attach it to 14 and continue: 141 / 81

Advancing to step 5:
81 goes into 141 1 times with a remainder of 60.
Use 1 as the next digit of our solution. 
Result so far: 491.0
Subtract 81 from 141 to get 60.
Bring next digit (0) of the dividend behind the 60 and repeat the process: 600 / 81

Step 6:
The number 81 fits into 600 7 times, leaving a remainder of 33.
Use 7 as the next digit of our solution. 
Result so far: 4917.0
If we take 567 away from 600, we end up with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Step 7:
330 divided by 81 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 4917.4
If we take 324 away from 330, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 8:
The number 81 fits into 60 0 times, leaving a remainder of 60.
The next digit of our result is 0. 
Result so far: 4917.4
If we subtract 0 from 60, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Moving on to step 9:
The number 81 fits into 600 7 times, leaving a remainder of 33.
The next digit of our result is 7. 
Result so far: 4917.407
If we take 567 away from 600, we end up with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Let's proceed to step 10:
If we divide 330 by 81, we get 4 and a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 4917.4074
The remainder is 6 after subtracting 324 from 330.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 11:
81 goes into 60 0 times with a remainder of 60.
Record the quotient 0 as the next digit in the result. 
Result so far: 4917.4074
If we take 0 away from 60, we end up with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 12:
The number 81 fits into 600 7 times, leaving a remainder of 33.
Write down 7 as next digit of the result. 
Result so far: 4917.407407
If we take 567 away from 600, we end up with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Step 13:
The number 81 fits into 330 4 times, leaving a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 4917.4074074
If we take 324 away from 330, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 14:
81 can be fit into 60 0 times, resulting in a remainder of 60.
The next digit of our result is 0. 
Result so far: 4917.4074074
Subtracting 0 from 60 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

The final result is 4917.4074074 with a remainder of 6e-08.