900396 ÷ 75 
The aim is to understand the frequency of 75 in 900396.

Let's proceed to step 1:
The number 75 fits into 9 0 times, leaving a remainder of 9.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Take the next digit (0) from the dividend and append it to 9, then repeat: 90 / 75

On to step 2:
75 can be fit into 90 1 times, resulting in a remainder of 15.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtracting 75 from 90 leaves us with 15.
Append the next digit (0) from the dividend to 15 and continue with: 150 / 75

On to step 3:
The number 75 fits into 150 2 times, leaving a remainder of 0.
Use 2 as the next digit of our solution. 
Result so far: 12.0
The remainder is 0 after subtracting 150 from 150.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 75

On to step 4:
When dividing 3 by 75, we get 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 120.0
If we take 0 away from 3, we end up with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 75

On to step 5:
75 goes into 39 0 times with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 1200.0
Subtract 0 from 39 to get 39.
Bring next digit (6) of the dividend behind the 39 and repeat the process: 396 / 75

Going ahead to step 6:
When dividing 396 by 75, we get 5 with a remainder of 21.
The next digit of our result is 5. 
Result so far: 12005.0
Deduct 375 from 396 and we're left with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Let's proceed to step 7:
If we divide 210 by 75, we get 2 and a remainder of 60.
Use 2 as the next digit of our solution. 
Result so far: 12005.2
Deduct 150 from 210 and we're left 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 8:
The number 75 fits into 600 8 times, leaving a remainder of 0.
The number 8 becomes the next digit in our result. 
Result so far: 12005.28
If we take 600 away from 600, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 9:
If we divide 0 by 75, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 12005.28
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 10:
The number 75 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 12005.28
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 12005.28, with a leftover of 0.0.