We look at the division of 396956 by 81 
The aim is to understand the frequency of 81 in 396956.

Going ahead to step 1:
If we divide 3 by 81, we get 0 and a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 81

On to step 2:
39 divided by 81 is 0 with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 39 and we're left with 39.
Grab the next digit (6) from the dividend, add it to 39, then carry on: 396 / 81

Moving on to step 3:
81 goes into 396 4 times with a remainder of 72.
The next digit of our result is 4. 
Result so far: 4.0
The remainder is 72 after subtracting 324 from 396.
Include the next digit (9) from the dividend after 72, then repeat: 729 / 81

Step 4:
81 can be fit into 729 9 times, resulting in a remainder of 0.
Record the quotient 9 as the next digit in the result. 
Result so far: 49.0
Subtracting 729 from 729 leaves us with 0.
Grab the next digit (5) from the dividend, add it to 0, then carry on: 5 / 81

Going ahead to step 5:
When dividing 5 by 81, we get 0 with a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 490.0
Subtract 0 from 5 to get 5.
Bring next digit (6) of the dividend behind the 5 and repeat the process: 56 / 81

Going ahead to step 6:
81 goes into 56 0 times with a remainder of 56.
The next digit of our result is 0. 
Result so far: 4900.0
Subtract 0 from 56 to get 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

On to step 7:
If we divide 560 by 81, we get 6 and a remainder of 74.
The number 6 becomes the next digit in our result. 
Result so far: 4900.6
If we subtract 486 from 560, we get 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

On to step 8:
81 can be fit into 740 9 times, resulting in a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 4900.69
The remainder is 11 after subtracting 729 from 740.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 9:
When dividing 110 by 81, we get 1 with a remainder of 29.
Record the quotient 1 as the next digit in the result. 
Result so far: 4900.691
Subtract 81 from 110 to get 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

Moving on to step 10:
290 divided by 81 is 3 with a remainder of 47.
Record the quotient 3 as the next digit in the result. 
Result so far: 4900.6913
Subtract 243 from 290 to get 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Advancing to step 11:
The number 81 fits into 470 5 times, leaving a remainder of 65.
Record the quotient 5 as the next digit in the result. 
Result so far: 4900.69135
Deduct 405 from 470 and we're left with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

On to step 12:
650 divided by 81 is 8 with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 4900.691358
Subtract 648 from 650 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 13:
81 goes into 20 0 times with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 4900.691358
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 14:
81 can be fit into 200 2 times, resulting in a remainder of 38.
The number 2 becomes the next digit in our result. 
Result so far: 4900.69135802
Deduct 162 from 200 and we're left with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

After the division, we end up with 4900.69135802 and a remainder of 3.8e-08.