We look at the division of 869569 by 91 
The aim is to understand the frequency of 91 in 869569.

Going ahead to step 1:
8 divided by 91 is 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Fetch the next digit (6) from the dividend, attach it to 8 and continue: 86 / 91

Let's proceed to step 2:
86 divided by 91 is 0 with a remainder of 86.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 86 to get 86.
Fetch the next digit (9) from the dividend, attach it to 86 and continue: 869 / 91

Let's proceed to step 3:
When dividing 869 by 91, we get 9 with a remainder of 50.
Write down 9 as next digit of the result. 
Result so far: 9.0
If we subtract 819 from 869, we get 50.
Append the next digit (5) from the dividend to 50 and continue with: 505 / 91

Advancing to step 4:
505 divided by 91 is 5 with a remainder of 50.
Write down 5 as next digit of the result. 
Result so far: 95.0
Subtract 455 from 505 to get 50.
Fetch the next digit (6) from the dividend, attach it to 50 and continue: 506 / 91

Step 5:
When dividing 506 by 91, we get 5 with a remainder of 51.
Write down 5 as next digit of the result. 
Result so far: 955.0
If we subtract 455 from 506, we get 51.
Fetch the next digit (9) from the dividend, attach it to 51 and continue: 519 / 91

Step 6:
91 goes into 519 5 times with a remainder of 64.
The next digit of our result is 5. 
Result so far: 9555.0
Subtracting 455 from 519 leaves us with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Moving on to step 7:
If we divide 640 by 91, we get 7 and a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 9555.7
If we subtract 637 from 640, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 8:
The number 91 fits into 30 0 times, leaving a remainder of 30.
Use 0 as the next digit of our solution. 
Result so far: 9555.7
If we subtract 0 from 30, we get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Let's proceed to step 9:
91 goes into 300 3 times with a remainder of 27.
Use 3 as the next digit of our solution. 
Result so far: 9555.703
Deduct 273 from 300 and we're left with 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Let's proceed to step 10:
The number 91 fits into 270 2 times, leaving a remainder of 88.
The next digit of our result is 2. 
Result so far: 9555.7032
If we subtract 182 from 270, we get 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Step 11:
880 divided by 91 is 9 with a remainder of 61.
Put 9 as the next digit of the answer. 
Result so far: 9555.70329
The remainder is 61 after subtracting 819 from 880.
Since there are no more digits in the dividend, we add a zero to the remainder making it 610, and continue the process.

Advancing to step 12:
The number 91 fits into 610 6 times, leaving a remainder of 64.
The number 6 becomes the next digit in our result. 
Result so far: 9555.703296
Subtracting 546 from 610 leaves us with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Going ahead to step 13:
When dividing 640 by 91, we get 7 with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 9555.7032967
Subtracting 637 from 640 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 14:
If we divide 30 by 91, we get 0 and a remainder of 30.
The next digit of our result is 0. 
Result so far: 9555.7032967
If we subtract 0 from 30, we get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

After the division, we end up with 9555.7032967 and a remainder of 3e-08.