We look at the division of 185129 by 15 
The aim is to understand the frequency of 15 in 185129.

Advancing to step 1:
If we divide 1 by 15, we get 0 and a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Fetch the next digit (8) from the dividend, attach it to 1 and continue: 18 / 15

Advancing to step 2:
If we divide 18 by 15, we get 1 and a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 15 away from 18, we end up with 3.
Fetch the next digit (5) from the dividend, attach it to 3 and continue: 35 / 15

Advancing to step 3:
When dividing 35 by 15, we get 2 with a remainder of 5.
Write down 2 as next digit of the result. 
Result so far: 12.0
Subtract 30 from 35 to get 5.
Fetch the next digit (1) from the dividend, attach it to 5 and continue: 51 / 15

On to step 4:
51 divided by 15 is 3 with a remainder of 6.
Record the quotient 3 as the next digit in the result. 
Result so far: 123.0
If we take 45 away from 51, we end up with 6.
Grab the next digit (2) from the dividend, add it to 6, then carry on: 62 / 15

On to step 5:
The number 15 fits into 62 4 times, leaving a remainder of 2.
Write down 4 as next digit of the result. 
Result so far: 1234.0
The remainder is 2 after subtracting 60 from 62.
Bring next digit (9) of the dividend behind the 2 and repeat the process: 29 / 15

Moving on to step 6:
The number 15 fits into 29 1 times, leaving a remainder of 14.
Put 1 as the next digit of the answer. 
Result so far: 12341.0
Subtracting 15 from 29 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Advancing to step 7:
140 divided by 15 is 9 with a remainder of 5.
Use 9 as the next digit of our solution. 
Result so far: 12341.9
If we take 135 away from 140, 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.

Let's proceed to step 8:
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: 12341.93
Subtracting 45 from 50 leaves us 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.

Step 9:
When dividing 50 by 15, we get 3 with a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 12341.933
Subtracting 45 from 50 leaves us 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.

The quotient of the division is 12341.933, and the remainder is 0.0005.