We look at the division of 358424 by 91 
The aim is to understand the frequency of 91 in 358424.

On to step 1:
The number 91 fits into 3 0 times, leaving a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Fetch the next digit (5) from the dividend, attach it to 3 and continue: 35 / 91

Advancing to step 2:
91 goes into 35 0 times with a remainder of 35.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 35 leaves us with 35.
Include the next digit (8) from the dividend after 35, then repeat: 358 / 91

Moving on to step 3:
91 can be fit into 358 3 times, resulting in a remainder of 85.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 85 after subtracting 273 from 358.
Take the next digit (4) from the dividend and append it to 85, then repeat: 854 / 91

Going ahead to step 4:
91 goes into 854 9 times with a remainder of 35.
Use 9 as the next digit of our solution. 
Result so far: 39.0
Deduct 819 from 854 and we're left with 35.
Append the next digit (2) from the dividend to 35 and continue with: 352 / 91

Let's proceed to step 5:
The number 91 fits into 352 3 times, leaving a remainder of 79.
Put 3 as the next digit of the answer. 
Result so far: 393.0
If we take 273 away from 352, we end up with 79.
Fetch the next digit (4) from the dividend, attach it to 79 and continue: 794 / 91

Step 6:
91 can be fit into 794 8 times, resulting in a remainder of 66.
Put 8 as the next digit of the answer. 
Result so far: 3938.0
If we take 728 away from 794, we end up with 66.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Step 7:
91 can be fit into 660 7 times, resulting in a remainder of 23.
Put 7 as the next digit of the answer. 
Result so far: 3938.7
Subtracting 637 from 660 leaves us with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Step 8:
The number 91 fits into 230 2 times, leaving a remainder of 48.
The number 2 becomes the next digit in our result. 
Result so far: 3938.72
Deduct 182 from 230 and we're left with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

On to step 9:
When dividing 480 by 91, we get 5 with a remainder of 25.
The next digit of our result is 5. 
Result so far: 3938.725
If we take 455 away from 480, we end up with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Going ahead to step 10:
If we divide 250 by 91, we get 2 and a remainder of 68.
Write down 2 as next digit of the result. 
Result so far: 3938.7252
Subtracting 182 from 250 leaves us with 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Going ahead to step 11:
680 divided by 91 is 7 with a remainder of 43.
Use 7 as the next digit of our solution. 
Result so far: 3938.72527
Subtracting 637 from 680 leaves us with 43.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

Going ahead to step 12:
430 divided by 91 is 4 with a remainder of 66.
Use 4 as the next digit of our solution. 
Result so far: 3938.725274
Subtracting 364 from 430 leaves us with 66.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Advancing to step 13:
The number 91 fits into 660 7 times, leaving a remainder of 23.
Record the quotient 7 as the next digit in the result. 
Result so far: 3938.7252747
If we take 637 away from 660, we end up with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Advancing to step 14:
91 can be fit into 230 2 times, resulting in a remainder of 48.
The next digit of our result is 2. 
Result so far: 3938.72527472
Deduct 182 from 230 and we're left with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

After the division, we end up with 3938.72527472 and a remainder of 4.8e-08.