We're dividing 421310 by 91 
The aim is to understand the frequency of 91 in 421310.

Step 1:
The number 91 fits into 4 0 times, leaving a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Include the next digit (2) from the dividend after 4, then repeat: 42 / 91

Going ahead to step 2:
91 can be fit into 42 0 times, resulting in a remainder of 42.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 42 and we're left with 42.
Fetch the next digit (1) from the dividend, attach it to 42 and continue: 421 / 91

Step 3:
421 divided by 91 is 4 with a remainder of 57.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
The remainder is 57 after subtracting 364 from 421.
Bring next digit (3) of the dividend behind the 57 and repeat the process: 573 / 91

Moving on to step 4:
91 goes into 573 6 times with a remainder of 27.
The next digit of our result is 6. 
Result so far: 46.0
The remainder is 27 after subtracting 546 from 573.
Bring next digit (1) of the dividend behind the 27 and repeat the process: 271 / 91

Going ahead to step 5:
271 divided by 91 is 2 with a remainder of 89.
Put 2 as the next digit of the answer. 
Result so far: 462.0
If we subtract 182 from 271, we get 89.
Take the next digit (0) from the dividend and append it to 89, then repeat: 890 / 91

Going ahead to step 6:
When dividing 890 by 91, we get 9 with a remainder of 71.
Use 9 as the next digit of our solution. 
Result so far: 4629.0
If we take 819 away from 890, we end up with 71.
Since there are no more digits in the dividend, we add a zero to the remainder making it 710, and continue the process.

Going ahead to step 7:
The number 91 fits into 710 7 times, leaving a remainder of 73.
Put 7 as the next digit of the answer. 
Result so far: 4629.7
Subtracting 637 from 710 leaves us with 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

On to step 8:
730 divided by 91 is 8 with a remainder of 2.
The next digit of our result is 8. 
Result so far: 4629.78
Deduct 728 from 730 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 9:
When dividing 20 by 91, we get 0 with a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 4629.78
If we take 0 away from 20, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 10:
91 goes into 200 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 4629.7802
If we take 182 away from 200, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 11:
180 divided by 91 is 1 with a remainder of 89.
Use 1 as the next digit of our solution. 
Result so far: 4629.78021
Subtract 91 from 180 to get 89.
Since there are no more digits in the dividend, we add a zero to the remainder making it 890, and continue the process.

On to step 12:
91 goes into 890 9 times with a remainder of 71.
Record the quotient 9 as the next digit in the result. 
Result so far: 4629.780219
The remainder is 71 after subtracting 819 from 890.
Since there are no more digits in the dividend, we add a zero to the remainder making it 710, and continue the process.

Step 13:
91 can be fit into 710 7 times, resulting in a remainder of 73.
The number 7 becomes the next digit in our result. 
Result so far: 4629.7802197
Subtracting 637 from 710 leaves us with 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Going ahead to step 14:
The number 91 fits into 730 8 times, leaving a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 4629.78021978
If we subtract 728 from 730, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

The quotient of the division is 4629.78021978, and the remainder is 2e-09.