We divide 15920 by 91
The aim is to understand the frequency of 91 in 15920.

Going ahead to step 1:
91 goes into 1 0 times with a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Grab the next digit (5) from the dividend, add it to 1, then carry on: 15 / 91

On to step 2:
91 can be fit into 15 0 times, resulting in a remainder of 15.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 15, we get 15.
Fetch the next digit (9) from the dividend, attach it to 15 and continue: 159 / 91

Let's proceed to step 3:
91 can be fit into 159 1 times, resulting in a remainder of 68.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 91 from 159 and we're left with 68.
Grab the next digit (2) from the dividend, add it to 68, then carry on: 682 / 91

Advancing to step 4:
91 can be fit into 682 7 times, resulting in a remainder of 45.
Use 7 as the next digit of our solution. 
Result so far: 17.0
If we subtract 637 from 682, we get 45.
Bring next digit (0) of the dividend behind the 45 and repeat the process: 450 / 91

Going ahead to step 5:
When dividing 450 by 91, we get 4 with a remainder of 86.
The next digit of our result is 4. 
Result so far: 174.0
Subtracting 364 from 450 leaves us with 86.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Going ahead to step 6:
91 can be fit into 860 9 times, resulting in a remainder of 41.
Write down 9 as next digit of the result. 
Result so far: 174.9
If we subtract 819 from 860, we get 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Moving on to step 7:
91 can be fit into 410 4 times, resulting in a remainder of 46.
Record the quotient 4 as the next digit in the result. 
Result so far: 174.94
The remainder is 46 after subtracting 364 from 410.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Let's proceed to step 8:
If we divide 460 by 91, we get 5 and a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 174.945
Subtracting 455 from 460 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.

Let's proceed to step 9:
91 goes into 50 0 times with a remainder of 50.
Record the quotient 0 as the next digit in the result. 
Result so far: 174.945
Deduct 0 from 50 and we're left with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 10:
When dividing 500 by 91, we get 5 with a remainder of 45.
The number 5 becomes the next digit in our result. 
Result so far: 174.94505
Subtracting 455 from 500 leaves us with 45.
Since there are no more digits in the dividend, we add a zero to the remainder making it 450, and continue the process.

Step 11:
91 goes into 450 4 times with a remainder of 86.
Put 4 as the next digit of the answer. 
Result so far: 174.945054
Deduct 364 from 450 and we're left with 86.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Advancing to step 12:
When dividing 860 by 91, we get 9 with a remainder of 41.
Use 9 as the next digit of our solution. 
Result so far: 174.9450549
If we subtract 819 from 860, we get 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Moving on to step 13:
If we divide 410 by 91, we get 4 and a remainder of 46.
Use 4 as the next digit of our solution. 
Result so far: 174.94505494
Subtract 364 from 410 to get 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

After the division, we end up with 174.94505494 and a remainder of 4.6e-08.