We're dividing 91238500 by 408 
The aim is to understand the frequency of 408 in 91238500.

Advancing to step 1:
The number 408 fits into 9 0 times, leaving a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 9, we get 9.
Take the next digit (1) from the dividend and append it to 9, then repeat: 91 / 408

On to step 2:
The number 408 fits into 91 0 times, leaving a remainder of 91.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 91 to get 91.
Include the next digit (2) from the dividend after 91, then repeat: 912 / 408

Going ahead to step 3:
The number 408 fits into 912 2 times, leaving a remainder of 96.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtracting 816 from 912 leaves us with 96.
Bring next digit (3) of the dividend behind the 96 and repeat the process: 963 / 408

Let's proceed to step 4:
When dividing 963 by 408, we get 2 with a remainder of 147.
Put 2 as the next digit of the answer. 
Result so far: 22.0
If we subtract 816 from 963, we get 147.
Append the next digit (8) from the dividend to 147 and continue with: 1478 / 408

Moving on to step 5:
If we divide 1478 by 408, we get 3 and a remainder of 254.
The next digit of our result is 3. 
Result so far: 223.0
If we subtract 1224 from 1478, we get 254.
Grab the next digit (5) from the dividend, add it to 254, then carry on: 2545 / 408

On to step 6:
2545 divided by 408 is 6 with a remainder of 97.
Use 6 as the next digit of our solution. 
Result so far: 2236.0
Subtract 2448 from 2545 to get 97.
Bring next digit (0) of the dividend behind the 97 and repeat the process: 970 / 408

Going ahead to step 7:
970 divided by 408 is 2 with a remainder of 154.
Write down 2 as next digit of the result. 
Result so far: 22362.0
Deduct 816 from 970 and we're left with 154.
Include the next digit (0) from the dividend after 154, then repeat: 1540 / 408

Going ahead to step 8:
1540 divided by 408 is 3 with a remainder of 316.
Record the quotient 3 as the next digit in the result. 
Result so far: 223623.0
If we take 1224 away from 1540, we end up with 316.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3160, and continue the process.

Going ahead to step 9:
3160 divided by 408 is 7 with a remainder of 304.
Record the quotient 7 as the next digit in the result. 
Result so far: 223623.7
If we take 2856 away from 3160, we end up with 304.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3040, and continue the process.

Advancing to step 10:
If we divide 3040 by 408, we get 7 and a remainder of 184.
The number 7 becomes the next digit in our result. 
Result so far: 223623.77
Subtract 2856 from 3040 to get 184.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1840, and continue the process.

The final outcome is 223623.77, with a leftover of 0.184.