438978 divided by 91 
The aim is to understand the frequency of 91 in 438978.

Moving on to step 1:
91 goes into 4 0 times with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Take the next digit (3) from the dividend and append it to 4, then repeat: 43 / 91

Step 2:
When dividing 43 by 91, we get 0 with a remainder of 43.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 43 after subtracting 0 from 43.
Grab the next digit (8) from the dividend, add it to 43, then carry on: 438 / 91

Going ahead to step 3:
If we divide 438 by 91, we get 4 and a remainder of 74.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
The remainder is 74 after subtracting 364 from 438.
Include the next digit (9) from the dividend after 74, then repeat: 749 / 91

Step 4:
The number 91 fits into 749 8 times, leaving a remainder of 21.
Use 8 as the next digit of our solution. 
Result so far: 48.0
Deduct 728 from 749 and we're left with 21.
Grab the next digit (7) from the dividend, add it to 21, then carry on: 217 / 91

Advancing to step 5:
91 goes into 217 2 times with a remainder of 35.
Put 2 as the next digit of the answer. 
Result so far: 482.0
Deduct 182 from 217 and we're left with 35.
Fetch the next digit (8) from the dividend, attach it to 35 and continue: 358 / 91

Advancing to step 6:
When dividing 358 by 91, we get 3 with a remainder of 85.
Write down 3 as next digit of the result. 
Result so far: 4823.0
If we take 273 away from 358, we end up with 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 850, and continue the process.

Advancing to step 7:
If we divide 850 by 91, we get 9 and a remainder of 31.
Record the quotient 9 as the next digit in the result. 
Result so far: 4823.9
If we subtract 819 from 850, we get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

On to step 8:
The number 91 fits into 310 3 times, leaving a remainder of 37.
Put 3 as the next digit of the answer. 
Result so far: 4823.93
The remainder is 37 after subtracting 273 from 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Step 9:
If we divide 370 by 91, we get 4 and a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 4823.934
The remainder is 6 after subtracting 364 from 370.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 10:
91 can be fit into 60 0 times, resulting in a remainder of 60.
Write down 0 as next digit of the result. 
Result so far: 4823.934
Subtracting 0 from 60 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 11:
91 can be fit into 600 6 times, resulting in a remainder of 54.
Put 6 as the next digit of the answer. 
Result so far: 4823.93406
If we take 546 away from 600, we end up with 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

Advancing to step 12:
91 goes into 540 5 times with a remainder of 85.
Record the quotient 5 as the next digit in the result. 
Result so far: 4823.934065
Subtract 455 from 540 to get 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 850, and continue the process.

Moving on to step 13:
91 can be fit into 850 9 times, resulting in a remainder of 31.
Record the quotient 9 as the next digit in the result. 
Result so far: 4823.9340659
Subtract 819 from 850 to get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

On to step 14:
91 goes into 310 3 times with a remainder of 37.
Use 3 as the next digit of our solution. 
Result so far: 4823.93406593
The remainder is 37 after subtracting 273 from 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

The final outcome is 4823.93406593, with a leftover of 3.7e-08.