Let's divide 390830 by 15
The aim is to understand the frequency of 15 in 390830.

Going ahead to step 1:
If we divide 3 by 15, we get 0 and a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 15

Advancing to step 2:
39 divided by 15 is 2 with a remainder of 9.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we subtract 30 from 39, we get 9.
Take the next digit (0) from the dividend and append it to 9, then repeat: 90 / 15

Moving on to step 3:
15 can be fit into 90 6 times, resulting in a remainder of 0.
Record the quotient 6 as the next digit in the result. 
Result so far: 26.0
If we subtract 90 from 90, we get 0.
Grab the next digit (8) from the dividend, add it to 0, then carry on: 8 / 15

Step 4:
When dividing 8 by 15, we get 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 260.0
If we take 0 away from 8, we end up with 8.
Include the next digit (3) from the dividend after 8, then repeat: 83 / 15

Advancing to step 5:
If we divide 83 by 15, we get 5 and a remainder of 8.
The number 5 becomes the next digit in our result. 
Result so far: 2605.0
Subtract 75 from 83 to get 8.
Bring next digit (0) of the dividend behind the 8 and repeat the process: 80 / 15

Going ahead to step 6:
When dividing 80 by 15, we get 5 with a remainder of 5.
The next digit of our result is 5. 
Result so far: 26055.0
Subtract 75 from 80 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 7:
15 can be fit into 50 3 times, resulting in a remainder of 5.
The number 3 becomes the next digit in our result. 
Result so far: 26055.3
Deduct 45 from 50 and we're left 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.

Going ahead to step 8:
The number 15 fits into 50 3 times, leaving a remainder of 5.
Put 3 as the next digit of the answer. 
Result so far: 26055.33
Subtract 45 from 50 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

The final result is 26055.33 with a remainder of 0.005.