810103 ÷ 15 
The aim is to understand the frequency of 15 in 810103.

Let's proceed to step 1:
The number 15 fits into 8 0 times, leaving a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Bring next digit (1) of the dividend behind the 8 and repeat the process: 81 / 15

On to step 2:
15 goes into 81 5 times with a remainder of 6.
The next digit of our result is 5. 
Result so far: 5.0
If we subtract 75 from 81, we get 6.
Grab the next digit (0) from the dividend, add it to 6, then carry on: 60 / 15

Step 3:
The number 15 fits into 60 4 times, leaving a remainder of 0.
The number 4 becomes the next digit in our result. 
Result so far: 54.0
Subtracting 60 from 60 leaves us with 0.
Append the next digit (1) from the dividend to 0 and continue with: 1 / 15

Going ahead to step 4:
If we divide 1 by 15, we get 0 and a remainder of 1.
The next digit of our result is 0. 
Result so far: 540.0
If we subtract 0 from 1, we get 1.
Take the next digit (0) from the dividend and append it to 1, then repeat: 10 / 15

Going ahead to step 5:
When dividing 10 by 15, we get 0 with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 5400.0
The remainder is 10 after subtracting 0 from 10.
Grab the next digit (3) from the dividend, add it to 10, then carry on: 103 / 15

Advancing to step 6:
The number 15 fits into 103 6 times, leaving a remainder of 13.
Put 6 as the next digit of the answer. 
Result so far: 54006.0
Subtracting 90 from 103 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Step 7:
The number 15 fits into 130 8 times, leaving a remainder of 10.
Use 8 as the next digit of our solution. 
Result so far: 54006.8
The remainder is 10 after subtracting 120 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 8:
If we divide 100 by 15, we get 6 and a remainder of 10.
Put 6 as the next digit of the answer. 
Result so far: 54006.86
If we subtract 90 from 100, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 9:
15 can be fit into 100 6 times, resulting in a remainder of 10.
Put 6 as the next digit of the answer. 
Result so far: 54006.866
Deduct 90 from 100 and we're left 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.

The final outcome is 54006.866, with a leftover of 0.001.