We look at the division of 909181 by 91 
The aim is to understand the frequency of 91 in 909181.

Going ahead to step 1:
When dividing 9 by 91, we get 0 with a remainder of 9.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Bring next digit (0) of the dividend behind the 9 and repeat the process: 90 / 91

Let's proceed to step 2:
90 divided by 91 is 0 with a remainder of 90.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 90 leaves us with 90.
Append the next digit (9) from the dividend to 90 and continue with: 909 / 91

Moving on to step 3:
909 divided by 91 is 9 with a remainder of 90.
The next digit of our result is 9. 
Result so far: 9.0
If we subtract 819 from 909, we get 90.
Append the next digit (1) from the dividend to 90 and continue with: 901 / 91

Advancing to step 4:
When dividing 901 by 91, we get 9 with a remainder of 82.
Write down 9 as next digit of the result. 
Result so far: 99.0
The remainder is 82 after subtracting 819 from 901.
Take the next digit (8) from the dividend and append it to 82, then repeat: 828 / 91

Let's proceed to step 5:
The number 91 fits into 828 9 times, leaving a remainder of 9.
Write down 9 as next digit of the result. 
Result so far: 999.0
Subtracting 819 from 828 leaves us with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 91

On to step 6:
91 can be fit into 91 1 times, resulting in a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 9991.0
Subtracting 91 from 91 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 7:
The number 91 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 9991.0
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
If we divide 0 by 91, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 9991.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 9991.0 with a remainder of 0.0.