We look at the division of 303113 by 81 
The aim is to understand the frequency of 81 in 303113.

Advancing to step 1:
3 divided by 81 is 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Append the next digit (0) from the dividend to 3 and continue with: 30 / 81

Going ahead to step 2:
81 can be fit into 30 0 times, resulting in a remainder of 30.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 30 leaves us with 30.
Append the next digit (3) from the dividend to 30 and continue with: 303 / 81

Moving on to step 3:
The number 81 fits into 303 3 times, leaving a remainder of 60.
Write down 3 as next digit of the result. 
Result so far: 3.0
If we subtract 243 from 303, we get 60.
Grab the next digit (1) from the dividend, add it to 60, then carry on: 601 / 81

On to step 4:
When dividing 601 by 81, we get 7 with a remainder of 34.
Record the quotient 7 as the next digit in the result. 
Result so far: 37.0
Subtracting 567 from 601 leaves us with 34.
Take the next digit (1) from the dividend and append it to 34, then repeat: 341 / 81

Let's proceed to step 5:
The number 81 fits into 341 4 times, leaving a remainder of 17.
The number 4 becomes the next digit in our result. 
Result so far: 374.0
Deduct 324 from 341 and we're left with 17.
Include the next digit (3) from the dividend after 17, then repeat: 173 / 81

Let's proceed to step 6:
When dividing 173 by 81, we get 2 with a remainder of 11.
Record the quotient 2 as the next digit in the result. 
Result so far: 3742.0
Deduct 162 from 173 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 7:
81 can be fit into 110 1 times, resulting in a remainder of 29.
Write down 1 as next digit of the result. 
Result so far: 3742.1
Subtracting 81 from 110 leaves us with 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

On to step 8:
The number 81 fits into 290 3 times, leaving a remainder of 47.
Use 3 as the next digit of our solution. 
Result so far: 3742.13
Subtracting 243 from 290 leaves us with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Step 9:
If we divide 470 by 81, we get 5 and a remainder of 65.
Put 5 as the next digit of the answer. 
Result so far: 3742.135
Subtracting 405 from 470 leaves us 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.

Advancing to step 10:
The number 81 fits into 650 8 times, leaving a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 3742.1358
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.

Let's proceed to step 11:
If we divide 20 by 81, we get 0 and a remainder of 20.
The next digit of our result is 0. 
Result so far: 3742.1358
Subtracting 0 from 20 leaves us 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 12:
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: 3742.135802
The remainder is 38 after subtracting 162 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Step 13:
When dividing 380 by 81, we get 4 with a remainder of 56.
The number 4 becomes the next digit in our result. 
Result so far: 3742.1358024
If we subtract 324 from 380, we 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 14:
560 divided by 81 is 6 with a remainder of 74.
Record the quotient 6 as the next digit in the result. 
Result so far: 3742.13580246
If we take 486 away from 560, we end up 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.

After the division, we end up with 3742.13580246 and a remainder of 7.4e-08.