We're dividing 852171 by 15 
The aim is to understand the frequency of 15 in 852171.

Advancing to step 1:
The number 15 fits into 8 0 times, leaving a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Include the next digit (5) from the dividend after 8, then repeat: 85 / 15

Advancing to step 2:
If we divide 85 by 15, we get 5 and a remainder of 10.
The next digit of our result is 5. 
Result so far: 5.0
The remainder is 10 after subtracting 75 from 85.
Append the next digit (2) from the dividend to 10 and continue with: 102 / 15

Advancing to step 3:
15 goes into 102 6 times with a remainder of 12.
Record the quotient 6 as the next digit in the result. 
Result so far: 56.0
Subtract 90 from 102 to get 12.
Append the next digit (1) from the dividend to 12 and continue with: 121 / 15

Advancing to step 4:
15 can be fit into 121 8 times, resulting in a remainder of 1.
Record the quotient 8 as the next digit in the result. 
Result so far: 568.0
Subtracting 120 from 121 leaves us with 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 15

On to step 5:
17 divided by 15 is 1 with a remainder of 2.
Put 1 as the next digit of the answer. 
Result so far: 5681.0
Deduct 15 from 17 and we're left with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 15

Moving on to step 6:
When dividing 21 by 15, we get 1 with a remainder of 6.
Record the quotient 1 as the next digit in the result. 
Result so far: 56811.0
Subtracting 15 from 21 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 7:
If we divide 60 by 15, we get 4 and a remainder of 0.
The number 4 becomes the next digit in our result. 
Result so far: 56811.4
Deduct 60 from 60 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 8:
0 divided by 15 is 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 56811.4
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 9:
15 can be fit into 0 0 times, resulting in a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 56811.4
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 56811.4 with a remaining 0.0.