We divide 391870 by 15
The aim is to understand the frequency of 15 in 391870.

Advancing to step 1:
15 goes into 3 0 times with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 15

Step 2:
15 can be fit into 39 2 times, resulting in a remainder of 9.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we take 30 away from 39, we end up with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 15

Let's proceed to step 3:
When dividing 91 by 15, we get 6 with a remainder of 1.
Write down 6 as next digit of the result. 
Result so far: 26.0
If we take 90 away from 91, we end up with 1.
Append the next digit (8) from the dividend to 1 and continue with: 18 / 15

On to step 4:
15 goes into 18 1 times with a remainder of 3.
Put 1 as the next digit of the answer. 
Result so far: 261.0
Subtracting 15 from 18 leaves us with 3.
Grab the next digit (7) from the dividend, add it to 3, then carry on: 37 / 15

Moving on to step 5:
15 can be fit into 37 2 times, resulting in a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 2612.0
The remainder is 7 after subtracting 30 from 37.
Bring next digit (0) of the dividend behind the 7 and repeat the process: 70 / 15

On to step 6:
15 can be fit into 70 4 times, resulting in a remainder of 10.
Put 4 as the next digit of the answer. 
Result so far: 26124.0
If we take 60 away from 70, 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:
If we divide 100 by 15, we get 6 and a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 26124.6
Subtracting 90 from 100 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.

Let's proceed to step 8:
When dividing 100 by 15, we get 6 with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 26124.66
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 result is 26124.66 with a remainder of 0.01.