635445 divided by 91 
The aim is to understand the frequency of 91 in 635445.

Step 1:
6 divided by 91 is 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 91

Advancing to step 2:
91 can be fit into 63 0 times, resulting in a remainder of 63.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 63, we get 63.
Fetch the next digit (5) from the dividend, attach it to 63 and continue: 635 / 91

Going ahead to step 3:
91 goes into 635 6 times with a remainder of 89.
Put 6 as the next digit of the answer. 
Result so far: 6.0
Subtracting 546 from 635 leaves us with 89.
Bring next digit (4) of the dividend behind the 89 and repeat the process: 894 / 91

Advancing to step 4:
The number 91 fits into 894 9 times, leaving a remainder of 75.
Record the quotient 9 as the next digit in the result. 
Result so far: 69.0
If we subtract 819 from 894, we get 75.
Bring next digit (4) of the dividend behind the 75 and repeat the process: 754 / 91

On to step 5:
91 goes into 754 8 times with a remainder of 26.
Write down 8 as next digit of the result. 
Result so far: 698.0
Subtract 728 from 754 to get 26.
Include the next digit (5) from the dividend after 26, then repeat: 265 / 91

On to step 6:
91 goes into 265 2 times with a remainder of 83.
Record the quotient 2 as the next digit in the result. 
Result so far: 6982.0
Deduct 182 from 265 and we're left with 83.
Since there are no more digits in the dividend, we add a zero to the remainder making it 830, and continue the process.

Moving on to step 7:
91 goes into 830 9 times with a remainder of 11.
Use 9 as the next digit of our solution. 
Result so far: 6982.9
The remainder is 11 after subtracting 819 from 830.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 8:
The number 91 fits into 110 1 times, leaving a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 6982.91
Subtracting 91 from 110 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 9:
91 goes into 190 2 times with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 6982.912
The remainder is 8 after subtracting 182 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 10:
If we divide 80 by 91, we get 0 and a remainder of 80.
The number 0 becomes the next digit in our result. 
Result so far: 6982.912
Subtracting 0 from 80 leaves us with 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Let's proceed to step 11:
When dividing 800 by 91, we get 8 with a remainder of 72.
The number 8 becomes the next digit in our result. 
Result so far: 6982.91208
If we take 728 away from 800, we end up with 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Moving on to step 12:
91 can be fit into 720 7 times, resulting in a remainder of 83.
Put 7 as the next digit of the answer. 
Result so far: 6982.912087
Subtracting 637 from 720 leaves us with 83.
Since there are no more digits in the dividend, we add a zero to the remainder making it 830, and continue the process.

Step 13:
91 can be fit into 830 9 times, resulting in a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 6982.9120879
Subtract 819 from 830 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.

On to step 14:
91 can be fit into 110 1 times, resulting in a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 6982.91208791
If we take 91 away from 110, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

The final result is 6982.91208791 with a remainder of 1.9e-08.