We look at the division of 688193 by 15 
The aim is to understand the frequency of 15 in 688193.

On to step 1:
15 can be fit into 6 0 times, resulting in a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Include the next digit (8) from the dividend after 6, then repeat: 68 / 15

Moving on to step 2:
When dividing 68 by 15, we get 4 with a remainder of 8.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 8 after subtracting 60 from 68.
Include the next digit (8) from the dividend after 8, then repeat: 88 / 15

Step 3:
When dividing 88 by 15, we get 5 with a remainder of 13.
Record the quotient 5 as the next digit in the result. 
Result so far: 45.0
If we subtract 75 from 88, we get 13.
Include the next digit (1) from the dividend after 13, then repeat: 131 / 15

On to step 4:
15 goes into 131 8 times with a remainder of 11.
Write down 8 as next digit of the result. 
Result so far: 458.0
The remainder is 11 after subtracting 120 from 131.
Take the next digit (9) from the dividend and append it to 11, then repeat: 119 / 15

Advancing to step 5:
The number 15 fits into 119 7 times, leaving a remainder of 14.
Use 7 as the next digit of our solution. 
Result so far: 4587.0
The remainder is 14 after subtracting 105 from 119.
Append the next digit (3) from the dividend to 14 and continue with: 143 / 15

Let's proceed to step 6:
The number 15 fits into 143 9 times, leaving a remainder of 8.
Put 9 as the next digit of the answer. 
Result so far: 45879.0
Subtracting 135 from 143 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 7:
The number 15 fits into 80 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 45879.5
The remainder is 5 after subtracting 75 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 8:
15 can be fit into 50 3 times, resulting in a remainder of 5.
Record the quotient 3 as the next digit in the result. 
Result so far: 45879.53
If we take 45 away from 50, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Moving on to step 9:
15 goes into 50 3 times with a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 45879.533
The remainder is 5 after subtracting 45 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Our division results in 45879.533 with a remaining 0.0005.