Let's divide 345809 by 91
The aim is to understand the frequency of 91 in 345809.

Advancing to step 1:
If we divide 3 by 91, we get 0 and a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Grab the next digit (4) from the dividend, add it to 3, then carry on: 34 / 91

Going ahead to step 2:
The number 91 fits into 34 0 times, leaving a remainder of 34.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 34, we get 34.
Include the next digit (5) from the dividend after 34, then repeat: 345 / 91

On to step 3:
When dividing 345 by 91, we get 3 with a remainder of 72.
Use 3 as the next digit of our solution. 
Result so far: 3.0
If we subtract 273 from 345, we get 72.
Fetch the next digit (8) from the dividend, attach it to 72 and continue: 728 / 91

Step 4:
When dividing 728 by 91, we get 8 with a remainder of 0.
The next digit of our result is 8. 
Result so far: 38.0
The remainder is 0 after subtracting 728 from 728.
Fetch the next digit (0) from the dividend, attach it to 0 and continue: 0 / 91

Advancing to step 5:
If we divide 0 by 91, we get 0 and a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 380.0
If we take 0 away from 0, we end up with 0.
Include the next digit (9) from the dividend after 0, then repeat: 9 / 91

Going ahead to step 6:
91 goes into 9 0 times with a remainder of 9.
The next digit of our result is 0. 
Result so far: 3800.0
Deduct 0 from 9 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 7:
90 divided by 91 is 0 with a remainder of 90.
Record the quotient 0 as the next digit in the result. 
Result so far: 3800.0
Subtract 0 from 90 to get 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Step 8:
If we divide 900 by 91, we get 9 and a remainder of 81.
Record the quotient 9 as the next digit in the result. 
Result so far: 3800.09
If we take 819 away from 900, we end up with 81.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

Advancing to step 9:
If we divide 810 by 91, we get 8 and a remainder of 82.
The number 8 becomes the next digit in our result. 
Result so far: 3800.098
If we take 728 away from 810, we end up with 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

Going ahead to step 10:
When dividing 820 by 91, we get 9 with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 3800.0989
If we take 819 away from 820, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 11:
The number 91 fits into 10 0 times, leaving a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 3800.0989
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 12:
If we divide 100 by 91, we get 1 and a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 3800.098901
Subtracting 91 from 100 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 13:
90 divided by 91 is 0 with a remainder of 90.
Put 0 as the next digit of the answer. 
Result so far: 3800.098901
Subtract 0 from 90 to get 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Advancing to step 14:
91 goes into 900 9 times with a remainder of 81.
Record the quotient 9 as the next digit in the result. 
Result so far: 3800.09890109
Deduct 819 from 900 and we're left with 81.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

After the division, we end up with 3800.09890109 and a remainder of 8.1e-08.