We look at the division of 811629 by 91 
The aim is to understand the frequency of 91 in 811629.

Going ahead to step 1:
If we divide 8 by 91, we get 0 and a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Fetch the next digit (1) from the dividend, attach it to 8 and continue: 81 / 91

Step 2:
81 divided by 91 is 0 with a remainder of 81.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 81 leaves us with 81.
Append the next digit (1) from the dividend to 81 and continue with: 811 / 91

Moving on to step 3:
If we divide 811 by 91, we get 8 and a remainder of 83.
Use 8 as the next digit of our solution. 
Result so far: 8.0
Subtract 728 from 811 to get 83.
Bring next digit (6) of the dividend behind the 83 and repeat the process: 836 / 91

Step 4:
If we divide 836 by 91, we get 9 and a remainder of 17.
Record the quotient 9 as the next digit in the result. 
Result so far: 89.0
Subtracting 819 from 836 leaves us with 17.
Include the next digit (2) from the dividend after 17, then repeat: 172 / 91

Moving on to step 5:
If we divide 172 by 91, we get 1 and a remainder of 81.
Write down 1 as next digit of the result. 
Result so far: 891.0
The remainder is 81 after subtracting 91 from 172.
Fetch the next digit (9) from the dividend, attach it to 81 and continue: 819 / 91

On to step 6:
When dividing 819 by 91, we get 9 with a remainder of 0.
The number 9 becomes the next digit in our result. 
Result so far: 8919.0
Subtract 819 from 819 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 7:
When dividing 0 by 91, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 8919.0
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.

Step 8:
If we divide 0 by 91, we get 0 and a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 8919.0
If we subtract 0 from 0, we get 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 quotient of the division is 8919.0, and the remainder is 0.0.