We look at the division of 554528 by 91 
The aim is to understand the frequency of 91 in 554528.

On to step 1:
91 can be fit into 5 0 times, resulting in a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 5, we end up with 5.
Fetch the next digit (5) from the dividend, attach it to 5 and continue: 55 / 91

On to step 2:
55 divided by 91 is 0 with a remainder of 55.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 55, we get 55.
Take the next digit (4) from the dividend and append it to 55, then repeat: 554 / 91

Going ahead to step 3:
554 divided by 91 is 6 with a remainder of 8.
Put 6 as the next digit of the answer. 
Result so far: 6.0
If we take 546 away from 554, we end up with 8.
Grab the next digit (5) from the dividend, add it to 8, then carry on: 85 / 91

Moving on to step 4:
The number 91 fits into 85 0 times, leaving a remainder of 85.
Put 0 as the next digit of the answer. 
Result so far: 60.0
If we take 0 away from 85, we end up with 85.
Take the next digit (2) from the dividend and append it to 85, then repeat: 852 / 91

Moving on to step 5:
The number 91 fits into 852 9 times, leaving a remainder of 33.
Put 9 as the next digit of the answer. 
Result so far: 609.0
If we subtract 819 from 852, we get 33.
Bring next digit (8) of the dividend behind the 33 and repeat the process: 338 / 91

Moving on to step 6:
When dividing 338 by 91, we get 3 with a remainder of 65.
The number 3 becomes the next digit in our result. 
Result so far: 6093.0
Deduct 273 from 338 and we're left with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

Advancing to step 7:
91 can be fit into 650 7 times, resulting in a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 6093.7
Subtract 637 from 650 to get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 8:
91 can be fit into 130 1 times, resulting in a remainder of 39.
The number 1 becomes the next digit in our result. 
Result so far: 6093.71
If we subtract 91 from 130, we get 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

Moving on to step 9:
When dividing 390 by 91, we get 4 with a remainder of 26.
Put 4 as the next digit of the answer. 
Result so far: 6093.714
If we take 364 away from 390, we end up with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Advancing to step 10:
If we divide 260 by 91, we get 2 and a remainder of 78.
Record the quotient 2 as the next digit in the result. 
Result so far: 6093.7142
If we take 182 away from 260, we end up with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Step 11:
When dividing 780 by 91, we get 8 with a remainder of 52.
Put 8 as the next digit of the answer. 
Result so far: 6093.71428
Subtract 728 from 780 to get 52.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Moving on to step 12:
When dividing 520 by 91, we get 5 with a remainder of 65.
Record the quotient 5 as the next digit in the result. 
Result so far: 6093.714285
Subtracting 455 from 520 leaves us with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

Moving on to step 13:
91 goes into 650 7 times with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 6093.7142857
Subtract 637 from 650 to get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 14:
91 can be fit into 130 1 times, resulting in a remainder of 39.
The number 1 becomes the next digit in our result. 
Result so far: 6093.71428571
Subtracting 91 from 130 leaves us with 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

After the division, we end up with 6093.71428571 and a remainder of 3.9e-08.