We look at the division of 663688 by 75 
The aim is to understand the frequency of 75 in 663688.

Moving on to step 1:
75 goes into 6 0 times with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Take the next digit (6) from the dividend and append it to 6, then repeat: 66 / 75

Let's proceed to step 2:
When dividing 66 by 75, we get 0 with a remainder of 66.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 66 and we're left with 66.
Fetch the next digit (3) from the dividend, attach it to 66 and continue: 663 / 75

Going ahead to step 3:
If we divide 663 by 75, we get 8 and a remainder of 63.
The next digit of our result is 8. 
Result so far: 8.0
The remainder is 63 after subtracting 600 from 663.
Fetch the next digit (6) from the dividend, attach it to 63 and continue: 636 / 75

On to step 4:
636 divided by 75 is 8 with a remainder of 36.
Record the quotient 8 as the next digit in the result. 
Result so far: 88.0
Subtract 600 from 636 to get 36.
Take the next digit (8) from the dividend and append it to 36, then repeat: 368 / 75

On to step 5:
When dividing 368 by 75, we get 4 with a remainder of 68.
Write down 4 as next digit of the result. 
Result so far: 884.0
The remainder is 68 after subtracting 300 from 368.
Bring next digit (8) of the dividend behind the 68 and repeat the process: 688 / 75

On to step 6:
If we divide 688 by 75, we get 9 and a remainder of 13.
Record the quotient 9 as the next digit in the result. 
Result so far: 8849.0
If we subtract 675 from 688, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 7:
The number 75 fits into 130 1 times, leaving a remainder of 55.
The number 1 becomes the next digit in our result. 
Result so far: 8849.1
If we subtract 75 from 130, we get 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

Advancing to step 8:
75 can be fit into 550 7 times, resulting in a remainder of 25.
The next digit of our result is 7. 
Result so far: 8849.17
Deduct 525 from 550 and we're left with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Let's proceed to step 9:
75 goes into 250 3 times with a remainder of 25.
Write down 3 as next digit of the result. 
Result so far: 8849.173
Subtract 225 from 250 to get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Going ahead to step 10:
250 divided by 75 is 3 with a remainder of 25.
Use 3 as the next digit of our solution. 
Result so far: 8849.1733
If we subtract 225 from 250, we get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

The final result is 8849.1733 with a remainder of 0.00025.