We're dividing 90604 by 15 
The aim is to understand the frequency of 15 in 90604.

On to step 1:
15 can be fit into 9 0 times, resulting in a remainder of 9.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 9, we get 9.
Take the next digit (0) from the dividend and append it to 9, then repeat: 90 / 15

Going ahead to step 2:
15 can be fit into 90 6 times, resulting in a remainder of 0.
Put 6 as the next digit of the answer. 
Result so far: 6.0
Deduct 90 from 90 and we're left with 0.
Include the next digit (6) from the dividend after 0, then repeat: 6 / 15

Going ahead to step 3:
If we divide 6 by 15, we get 0 and a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 60.0
Subtracting 0 from 6 leaves us with 6.
Include the next digit (0) from the dividend after 6, then repeat: 60 / 15

On to step 4:
The number 15 fits into 60 4 times, leaving a remainder of 0.
The next digit of our result is 4. 
Result so far: 604.0
If we take 60 away from 60, we end up with 0.
Append the next digit (4) from the dividend to 0 and continue with: 4 / 15

Advancing to step 5:
15 can be fit into 4 0 times, resulting in a remainder of 4.
The next digit of our result is 0. 
Result so far: 6040.0
If we take 0 away from 4, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 6:
15 goes into 40 2 times with a remainder of 10.
The number 2 becomes the next digit in our result. 
Result so far: 6040.2
If we take 30 away from 40, we end up 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.

Going ahead to step 7:
15 goes into 100 6 times with a remainder of 10.
The next digit of our result is 6. 
Result so far: 6040.26
If we take 90 away from 100, we end up 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.

Going ahead to step 8:
15 goes into 100 6 times with a remainder of 10.
Record the quotient 6 as the next digit in the result. 
Result so far: 6040.266
Subtract 90 from 100 to 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.

The final outcome is 6040.266, with a leftover of 0.001.