We're dividing 571648 by 91 
The aim is to understand the frequency of 91 in 571648.

Step 1:
91 goes into 5 0 times with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Fetch the next digit (7) from the dividend, attach it to 5 and continue: 57 / 91

On to step 2:
If we divide 57 by 91, we get 0 and a remainder of 57.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 57, we end up with 57.
Bring next digit (1) of the dividend behind the 57 and repeat the process: 571 / 91

Step 3:
571 divided by 91 is 6 with a remainder of 25.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
The remainder is 25 after subtracting 546 from 571.
Grab the next digit (6) from the dividend, add it to 25, then carry on: 256 / 91

On to step 4:
When dividing 256 by 91, we get 2 with a remainder of 74.
The next digit of our result is 2. 
Result so far: 62.0
Subtract 182 from 256 to get 74.
Include the next digit (4) from the dividend after 74, then repeat: 744 / 91

On to step 5:
91 can be fit into 744 8 times, resulting in a remainder of 16.
The next digit of our result is 8. 
Result so far: 628.0
Subtracting 728 from 744 leaves us with 16.
Grab the next digit (8) from the dividend, add it to 16, then carry on: 168 / 91

Moving on to step 6:
91 goes into 168 1 times with a remainder of 77.
The next digit of our result is 1. 
Result so far: 6281.0
Deduct 91 from 168 and we're left with 77.
Since there are no more digits in the dividend, we add a zero to the remainder making it 770, and continue the process.

Step 7:
770 divided by 91 is 8 with a remainder of 42.
The next digit of our result is 8. 
Result so far: 6281.8
Subtract 728 from 770 to get 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Advancing to step 8:
420 divided by 91 is 4 with a remainder of 56.
Record the quotient 4 as the next digit in the result. 
Result so far: 6281.84
The remainder is 56 after subtracting 364 from 420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Moving on to step 9:
91 goes into 560 6 times with a remainder of 14.
Put 6 as the next digit of the answer. 
Result so far: 6281.846
Subtract 546 from 560 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

On to step 10:
91 can be fit into 140 1 times, resulting in a remainder of 49.
Put 1 as the next digit of the answer. 
Result so far: 6281.8461
If we take 91 away from 140, we end up with 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

Step 11:
The number 91 fits into 490 5 times, leaving a remainder of 35.
Use 5 as the next digit of our solution. 
Result so far: 6281.84615
If we take 455 away from 490, we end up with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

Step 12:
When dividing 350 by 91, we get 3 with a remainder of 77.
Write down 3 as next digit of the result. 
Result so far: 6281.846153
Deduct 273 from 350 and we're left with 77.
Since there are no more digits in the dividend, we add a zero to the remainder making it 770, and continue the process.

Step 13:
If we divide 770 by 91, we get 8 and a remainder of 42.
Use 8 as the next digit of our solution. 
Result so far: 6281.8461538
Deduct 728 from 770 and we're left with 42.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Advancing to step 14:
The number 91 fits into 420 4 times, leaving a remainder of 56.
Put 4 as the next digit of the answer. 
Result so far: 6281.84615384
The remainder is 56 after subtracting 364 from 420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

After the division, we end up with 6281.84615384 and a remainder of 5.6e-08.