181691 divided by 15 
The aim is to understand the frequency of 15 in 181691.

Advancing to step 1:
The number 15 fits into 1 0 times, leaving a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Fetch the next digit (8) from the dividend, attach it to 1 and continue: 18 / 15

Moving on to step 2:
15 goes into 18 1 times with a remainder of 3.
Write down 1 as next digit of the result. 
Result so far: 1.0
Deduct 15 from 18 and we're left with 3.
Include the next digit (1) from the dividend after 3, then repeat: 31 / 15

Going ahead to step 3:
15 can be fit into 31 2 times, resulting in a remainder of 1.
Record the quotient 2 as the next digit in the result. 
Result so far: 12.0
If we take 30 away from 31, we end up with 1.
Include the next digit (6) from the dividend after 1, then repeat: 16 / 15

On to step 4:
If we divide 16 by 15, we get 1 and a remainder of 1.
The next digit of our result is 1. 
Result so far: 121.0
If we take 15 away from 16, we end up with 1.
Include the next digit (9) from the dividend after 1, then repeat: 19 / 15

Advancing to step 5:
19 divided by 15 is 1 with a remainder of 4.
Use 1 as the next digit of our solution. 
Result so far: 1211.0
The remainder is 4 after subtracting 15 from 19.
Grab the next digit (1) from the dividend, add it to 4, then carry on: 41 / 15

On to step 6:
15 can be fit into 41 2 times, resulting in a remainder of 11.
Write down 2 as next digit of the result. 
Result so far: 12112.0
Subtract 30 from 41 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 7:
15 can be fit into 110 7 times, resulting in a remainder of 5.
The number 7 becomes the next digit in our result. 
Result so far: 12112.7
If we take 105 away from 110, 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.

Advancing to step 8:
If we divide 50 by 15, we get 3 and a remainder of 5.
Record the quotient 3 as the next digit in the result. 
Result so far: 12112.73
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.

Moving on to step 9:
15 goes into 50 3 times with a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 12112.733
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.

The final outcome is 12112.733, with a leftover of 0.0005.