We're dividing 90408739 by 404 
The aim is to understand the frequency of 404 in 90408739.

On to step 1:
The number 404 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 take 0 away from 9, we end up with 9.
Append the next digit (0) from the dividend to 9 and continue with: 90 / 404

On to step 2:
404 goes into 90 0 times with a remainder of 90.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 90 to get 90.
Bring next digit (4) of the dividend behind the 90 and repeat the process: 904 / 404

On to step 3:
The number 404 fits into 904 2 times, leaving a remainder of 96.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Subtract 808 from 904 to get 96.
Include the next digit (0) from the dividend after 96, then repeat: 960 / 404

Advancing to step 4:
960 divided by 404 is 2 with a remainder of 152.
Record the quotient 2 as the next digit in the result. 
Result so far: 22.0
The remainder is 152 after subtracting 808 from 960.
Include the next digit (8) from the dividend after 152, then repeat: 1528 / 404

Let's proceed to step 5:
1528 divided by 404 is 3 with a remainder of 316.
Record the quotient 3 as the next digit in the result. 
Result so far: 223.0
Deduct 1212 from 1528 and we're left with 316.
Bring next digit (7) of the dividend behind the 316 and repeat the process: 3167 / 404

Step 6:
The number 404 fits into 3167 7 times, leaving a remainder of 339.
Put 7 as the next digit of the answer. 
Result so far: 2237.0
The remainder is 339 after subtracting 2828 from 3167.
Bring next digit (3) of the dividend behind the 339 and repeat the process: 3393 / 404

Step 7:
404 goes into 3393 8 times with a remainder of 161.
The next digit of our result is 8. 
Result so far: 22378.0
If we take 3232 away from 3393, we end up with 161.
Fetch the next digit (9) from the dividend, attach it to 161 and continue: 1619 / 404

Let's proceed to step 8:
404 can be fit into 1619 4 times, resulting in a remainder of 3.
The number 4 becomes the next digit in our result. 
Result so far: 223784.0
Subtract 1616 from 1619 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 9:
404 can be fit into 30 0 times, resulting in a remainder of 30.
Use 0 as the next digit of our solution. 
Result so far: 223784.0
If we take 0 away from 30, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

On to step 10:
If we divide 300 by 404, we get 0 and a remainder of 300.
The number 0 becomes the next digit in our result. 
Result so far: 223784.0
The remainder is 300 after subtracting 0 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

The final outcome is 223784.0, with a leftover of 0.3.