We look at the division of 516422 by 81 
The aim is to understand the frequency of 81 in 516422.

On to step 1:
When dividing 5 by 81, we get 0 with a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Include the next digit (1) from the dividend after 5, then repeat: 51 / 81

Going ahead to step 2:
81 goes into 51 0 times with a remainder of 51.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 51 leaves us with 51.
Take the next digit (6) from the dividend and append it to 51, then repeat: 516 / 81

On to step 3:
516 divided by 81 is 6 with a remainder of 30.
Record the quotient 6 as the next digit in the result. 
Result so far: 6.0
Subtracting 486 from 516 leaves us with 30.
Bring next digit (4) of the dividend behind the 30 and repeat the process: 304 / 81

On to step 4:
304 divided by 81 is 3 with a remainder of 61.
Write down 3 as next digit of the result. 
Result so far: 63.0
The remainder is 61 after subtracting 243 from 304.
Append the next digit (2) from the dividend to 61 and continue with: 612 / 81

Moving on to step 5:
When dividing 612 by 81, we get 7 with a remainder of 45.
Record the quotient 7 as the next digit in the result. 
Result so far: 637.0
If we subtract 567 from 612, we get 45.
Bring next digit (2) of the dividend behind the 45 and repeat the process: 452 / 81

Step 6:
If we divide 452 by 81, we get 5 and a remainder of 47.
The next digit of our result is 5. 
Result so far: 6375.0
If we subtract 405 from 452, we 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.

On to step 7:
81 can be fit into 470 5 times, resulting in a remainder of 65.
Record the quotient 5 as the next digit in the result. 
Result so far: 6375.5
Subtract 405 from 470 to get 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

Step 8:
If we divide 650 by 81, we get 8 and a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 6375.58
The remainder is 2 after subtracting 648 from 650.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 9:
81 can be fit into 20 0 times, resulting in a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 6375.58
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 10:
If we divide 200 by 81, we get 2 and a remainder of 38.
The number 2 becomes the next digit in our result. 
Result so far: 6375.5802
If we take 162 away from 200, we end up 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.

Going ahead to step 11:
81 can be fit into 380 4 times, resulting in a remainder of 56.
The next digit of our result is 4. 
Result so far: 6375.58024
If we take 324 away from 380, we end up with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Let's proceed to step 12:
560 divided by 81 is 6 with a remainder of 74.
Use 6 as the next digit of our solution. 
Result so far: 6375.580246
Subtracting 486 from 560 leaves us with 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Let's proceed to step 13:
If we divide 740 by 81, we get 9 and a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 6375.5802469
Subtract 729 from 740 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 14:
If we divide 110 by 81, we get 1 and a remainder of 29.
Use 1 as the next digit of our solution. 
Result so far: 6375.58024691
If we subtract 81 from 110, we 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.

Our division results in 6375.58024691 with a remaining 2.9e-08.