351668 divided by 91 
The aim is to understand the frequency of 91 in 351668.

Advancing to step 1:
91 can be fit into 3 0 times, resulting in a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Take the next digit (5) from the dividend and append it to 3, then repeat: 35 / 91

Going ahead to step 2:
When dividing 35 by 91, we get 0 with a remainder of 35.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 35, we get 35.
Bring next digit (1) of the dividend behind the 35 and repeat the process: 351 / 91

Going ahead to step 3:
The number 91 fits into 351 3 times, leaving a remainder of 78.
The next digit of our result is 3. 
Result so far: 3.0
If we subtract 273 from 351, we get 78.
Bring next digit (6) of the dividend behind the 78 and repeat the process: 786 / 91

Moving on to step 4:
When dividing 786 by 91, we get 8 with a remainder of 58.
Record the quotient 8 as the next digit in the result. 
Result so far: 38.0
Subtract 728 from 786 to get 58.
Fetch the next digit (6) from the dividend, attach it to 58 and continue: 586 / 91

On to step 5:
91 can be fit into 586 6 times, resulting in a remainder of 40.
The number 6 becomes the next digit in our result. 
Result so far: 386.0
If we take 546 away from 586, we end up with 40.
Take the next digit (8) from the dividend and append it to 40, then repeat: 408 / 91

Moving on to step 6:
When dividing 408 by 91, we get 4 with a remainder of 44.
Record the quotient 4 as the next digit in the result. 
Result so far: 3864.0
If we take 364 away from 408, we end up with 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Let's proceed to step 7:
440 divided by 91 is 4 with a remainder of 76.
Use 4 as the next digit of our solution. 
Result so far: 3864.4
Deduct 364 from 440 and we're left with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Moving on to step 8:
If we divide 760 by 91, we get 8 and a remainder of 32.
Use 8 as the next digit of our solution. 
Result so far: 3864.48
Deduct 728 from 760 and we're left with 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Advancing to step 9:
When dividing 320 by 91, we get 3 with a remainder of 47.
Use 3 as the next digit of our solution. 
Result so far: 3864.483
The remainder is 47 after subtracting 273 from 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Going ahead to step 10:
91 goes into 470 5 times with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 3864.4835
If we take 455 away from 470, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 11:
If we divide 150 by 91, we get 1 and a remainder of 59.
The number 1 becomes the next digit in our result. 
Result so far: 3864.48351
Subtract 91 from 150 to get 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

Advancing to step 12:
When dividing 590 by 91, we get 6 with a remainder of 44.
Put 6 as the next digit of the answer. 
Result so far: 3864.483516
The remainder is 44 after subtracting 546 from 590.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Step 13:
91 goes into 440 4 times with a remainder of 76.
Put 4 as the next digit of the answer. 
Result so far: 3864.4835164
If we subtract 364 from 440, we get 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Moving on to step 14:
91 goes into 760 8 times with a remainder of 32.
Use 8 as the next digit of our solution. 
Result so far: 3864.48351648
Subtracting 728 from 760 leaves us with 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Our division results in 3864.48351648 with a remaining 3.2e-08.