We look at the division of 420435 by 75 
The aim is to understand the frequency of 75 in 420435.

On to step 1:
If we divide 4 by 75, we get 0 and a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 75

Step 2:
75 goes into 42 0 times with a remainder of 42.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 42, we end up with 42.
Append the next digit (0) from the dividend to 42 and continue with: 420 / 75

Going ahead to step 3:
75 can be fit into 420 5 times, resulting in a remainder of 45.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
If we subtract 375 from 420, we get 45.
Include the next digit (4) from the dividend after 45, then repeat: 454 / 75

On to step 4:
454 divided by 75 is 6 with a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 56.0
If we take 450 away from 454, we end up with 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 75

Moving on to step 5:
The number 75 fits into 43 0 times, leaving a remainder of 43.
The next digit of our result is 0. 
Result so far: 560.0
Deduct 0 from 43 and we're left with 43.
Append the next digit (5) from the dividend to 43 and continue with: 435 / 75

Advancing to step 6:
75 can be fit into 435 5 times, resulting in a remainder of 60.
The next digit of our result is 5. 
Result so far: 5605.0
Subtract 375 from 435 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 7:
When dividing 600 by 75, we get 8 with a remainder of 0.
The next digit of our result is 8. 
Result so far: 5605.8
Subtracting 600 from 600 leaves us 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.

Advancing to step 8:
When dividing 0 by 75, we get 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 5605.8
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 9:
The number 75 fits into 0 0 times, leaving a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 5605.8
The remainder is 0 after subtracting 0 from 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 5605.8, with a leftover of 0.0.