We're dividing 83458 by 91 
The aim is to understand the frequency of 91 in 83458.

On to step 1:
91 goes into 8 0 times with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Grab the next digit (3) from the dividend, add it to 8, then carry on: 83 / 91

On to step 2:
The number 91 fits into 83 0 times, leaving a remainder of 83.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 83 to get 83.
Grab the next digit (4) from the dividend, add it to 83, then carry on: 834 / 91

Step 3:
91 can be fit into 834 9 times, resulting in a remainder of 15.
The number 9 becomes the next digit in our result. 
Result so far: 9.0
If we subtract 819 from 834, we get 15.
Fetch the next digit (5) from the dividend, attach it to 15 and continue: 155 / 91

On to step 4:
91 can be fit into 155 1 times, resulting in a remainder of 64.
Write down 1 as next digit of the result. 
Result so far: 91.0
If we subtract 91 from 155, we get 64.
Bring next digit (8) of the dividend behind the 64 and repeat the process: 648 / 91

Step 5:
91 goes into 648 7 times with a remainder of 11.
Put 7 as the next digit of the answer. 
Result so far: 917.0
The remainder is 11 after subtracting 637 from 648.
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 6:
91 goes into 110 1 times with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 917.1
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.

Moving on to step 7:
190 divided by 91 is 2 with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 917.12
If we take 182 away from 190, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 8:
The number 91 fits into 80 0 times, leaving a remainder of 80.
Write down 0 as next digit of the result. 
Result so far: 917.12
If we take 0 away from 80, we end up 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.

Step 9:
800 divided by 91 is 8 with a remainder of 72.
Record the quotient 8 as the next digit in the result. 
Result so far: 917.1208
The remainder is 72 after subtracting 728 from 800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Step 10:
The number 91 fits into 720 7 times, leaving a remainder of 83.
Write down 7 as next digit of the result. 
Result so far: 917.12087
Deduct 637 from 720 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.

Advancing to step 11:
91 goes into 830 9 times with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 917.120879
If we take 819 away from 830, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 12:
91 goes into 110 1 times with a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 917.1208791
If we subtract 91 from 110, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 13:
When dividing 190 by 91, we get 2 with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 917.12087912
Subtract 182 from 190 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

The final outcome is 917.12087912, with a leftover of 8e-09.