We look at the division of 573187 by 91 
The aim is to understand the frequency of 91 in 573187.

Moving on to step 1:
If we divide 5 by 91, we get 0 and 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.
Append the next digit (7) from the dividend to 5 and continue with: 57 / 91

Moving on to step 2:
When dividing 57 by 91, we get 0 with a remainder of 57.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 57 after subtracting 0 from 57.
Fetch the next digit (3) from the dividend, attach it to 57 and continue: 573 / 91

Moving on to step 3:
If we divide 573 by 91, we get 6 and a remainder of 27.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
If we subtract 546 from 573, we get 27.
Grab the next digit (1) from the dividend, add it to 27, then carry on: 271 / 91

Let's proceed to step 4:
When dividing 271 by 91, we get 2 with a remainder of 89.
Put 2 as the next digit of the answer. 
Result so far: 62.0
If we subtract 182 from 271, we get 89.
Fetch the next digit (8) from the dividend, attach it to 89 and continue: 898 / 91

Going ahead to step 5:
If we divide 898 by 91, we get 9 and a remainder of 79.
Put 9 as the next digit of the answer. 
Result so far: 629.0
Deduct 819 from 898 and we're left with 79.
Append the next digit (7) from the dividend to 79 and continue with: 797 / 91

Let's proceed to step 6:
91 can be fit into 797 8 times, resulting in a remainder of 69.
Use 8 as the next digit of our solution. 
Result so far: 6298.0
Subtracting 728 from 797 leaves us with 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 690, and continue the process.

Going ahead to step 7:
When dividing 690 by 91, we get 7 with a remainder of 53.
Write down 7 as next digit of the result. 
Result so far: 6298.7
If we take 637 away from 690, we end up with 53.
Since there are no more digits in the dividend, we add a zero to the remainder making it 530, and continue the process.

Advancing to step 8:
When dividing 530 by 91, we get 5 with a remainder of 75.
Record the quotient 5 as the next digit in the result. 
Result so far: 6298.75
Deduct 455 from 530 and we're left with 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

On to step 9:
750 divided by 91 is 8 with a remainder of 22.
The number 8 becomes the next digit in our result. 
Result so far: 6298.758
Subtracting 728 from 750 leaves us with 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Moving on to step 10:
If we divide 220 by 91, we get 2 and a remainder of 38.
Write down 2 as next digit of the result. 
Result so far: 6298.7582
Subtract 182 from 220 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Let's proceed to step 11:
When dividing 380 by 91, we get 4 with a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 6298.75824
Subtracting 364 from 380 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 12:
The number 91 fits into 160 1 times, leaving a remainder of 69.
The number 1 becomes the next digit in our result. 
Result so far: 6298.758241
If we subtract 91 from 160, we get 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 690, and continue the process.

On to step 13:
When dividing 690 by 91, we get 7 with a remainder of 53.
The next digit of our result is 7. 
Result so far: 6298.7582417
Deduct 637 from 690 and we're left with 53.
Since there are no more digits in the dividend, we add a zero to the remainder making it 530, and continue the process.

Going ahead to step 14:
530 divided by 91 is 5 with a remainder of 75.
The next digit of our result is 5. 
Result so far: 6298.75824175
Deduct 455 from 530 and we're left with 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

The final result is 6298.75824175 with a remainder of 7.5e-08.