We look at the division of 743968 by 81 
The aim is to understand the frequency of 81 in 743968.

Let's proceed to step 1:
When dividing 7 by 81, we get 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Include the next digit (4) from the dividend after 7, then repeat: 74 / 81

On to step 2:
74 divided by 81 is 0 with a remainder of 74.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 74 to get 74.
Append the next digit (3) from the dividend to 74 and continue with: 743 / 81

Moving on to step 3:
743 divided by 81 is 9 with a remainder of 14.
Use 9 as the next digit of our solution. 
Result so far: 9.0
If we take 729 away from 743, we end up with 14.
Include the next digit (9) from the dividend after 14, then repeat: 149 / 81

Advancing to step 4:
If we divide 149 by 81, we get 1 and a remainder of 68.
Use 1 as the next digit of our solution. 
Result so far: 91.0
If we subtract 81 from 149, we get 68.
Fetch the next digit (6) from the dividend, attach it to 68 and continue: 686 / 81

On to step 5:
If we divide 686 by 81, we get 8 and a remainder of 38.
Record the quotient 8 as the next digit in the result. 
Result so far: 918.0
The remainder is 38 after subtracting 648 from 686.
Include the next digit (8) from the dividend after 38, then repeat: 388 / 81

Step 6:
388 divided by 81 is 4 with a remainder of 64.
Put 4 as the next digit of the answer. 
Result so far: 9184.0
Subtracting 324 from 388 leaves us with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Advancing to step 7:
The number 81 fits into 640 7 times, leaving a remainder of 73.
Record the quotient 7 as the next digit in the result. 
Result so far: 9184.7
Subtracting 567 from 640 leaves us with 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Going ahead to step 8:
730 divided by 81 is 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 9184.79
If we subtract 729 from 730, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 9:
81 goes into 10 0 times with a remainder of 10.
The next digit of our result is 0. 
Result so far: 9184.79
Subtracting 0 from 10 leaves us 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 10:
When dividing 100 by 81, we get 1 with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 9184.7901
If we subtract 81 from 100, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 11:
81 goes into 190 2 times with a remainder of 28.
The number 2 becomes the next digit in our result. 
Result so far: 9184.79012
If we subtract 162 from 190, we get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Step 12:
The number 81 fits into 280 3 times, leaving a remainder of 37.
The number 3 becomes the next digit in our result. 
Result so far: 9184.790123
If we take 243 away from 280, we end up 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 13:
370 divided by 81 is 4 with a remainder of 46.
The next digit of our result is 4. 
Result so far: 9184.7901234
If we subtract 324 from 370, we get 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Moving on to step 14:
If we divide 460 by 81, we get 5 and a remainder of 55.
Record the quotient 5 as the next digit in the result. 
Result so far: 9184.79012345
Subtracting 405 from 460 leaves us with 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

The final outcome is 9184.79012345, with a leftover of 5.5e-08.