We look at the division of 712021 by 91 
The aim is to understand the frequency of 91 in 712021.

Advancing to step 1:
When dividing 7 by 91, we get 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Fetch the next digit (1) from the dividend, attach it to 7 and continue: 71 / 91

On to step 2:
91 can be fit into 71 0 times, resulting in a remainder of 71.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 71, we get 71.
Grab the next digit (2) from the dividend, add it to 71, then carry on: 712 / 91

Advancing to step 3:
When dividing 712 by 91, we get 7 with a remainder of 75.
Write down 7 as next digit of the result. 
Result so far: 7.0
If we subtract 637 from 712, we get 75.
Fetch the next digit (0) from the dividend, attach it to 75 and continue: 750 / 91

Moving on to step 4:
91 can be fit into 750 8 times, resulting in a remainder of 22.
Record the quotient 8 as the next digit in the result. 
Result so far: 78.0
The remainder is 22 after subtracting 728 from 750.
Append the next digit (2) from the dividend to 22 and continue with: 222 / 91

Advancing to step 5:
91 goes into 222 2 times with a remainder of 40.
The number 2 becomes the next digit in our result. 
Result so far: 782.0
If we subtract 182 from 222, we get 40.
Take the next digit (1) from the dividend and append it to 40, then repeat: 401 / 91

On to step 6:
When dividing 401 by 91, we get 4 with a remainder of 37.
The number 4 becomes the next digit in our result. 
Result so far: 7824.0
Subtract 364 from 401 to get 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Let's proceed to step 7:
The number 91 fits into 370 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 7824.4
Subtract 364 from 370 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 8:
If we divide 60 by 91, we get 0 and a remainder of 60.
Put 0 as the next digit of the answer. 
Result so far: 7824.4
If we subtract 0 from 60, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 9:
600 divided by 91 is 6 with a remainder of 54.
Use 6 as the next digit of our solution. 
Result so far: 7824.406
Deduct 546 from 600 and we're left with 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

Step 10:
540 divided by 91 is 5 with a remainder of 85.
Use 5 as the next digit of our solution. 
Result so far: 7824.4065
Subtract 455 from 540 to get 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 850, and continue the process.

Moving on to step 11:
850 divided by 91 is 9 with a remainder of 31.
Write down 9 as next digit of the result. 
Result so far: 7824.40659
Deduct 819 from 850 and we're left with 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Step 12:
The number 91 fits into 310 3 times, leaving a remainder of 37.
The next digit of our result is 3. 
Result so far: 7824.406593
Subtracting 273 from 310 leaves us with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Advancing to step 13:
91 can be fit into 370 4 times, resulting in a remainder of 6.
The next digit of our result is 4. 
Result so far: 7824.4065934
If we subtract 364 from 370, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 14:
If we divide 60 by 91, we get 0 and a remainder of 60.
Write down 0 as next digit of the result. 
Result so far: 7824.4065934
Deduct 0 from 60 and we're left with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

The final result is 7824.4065934 with a remainder of 6e-08.