575921 ÷ 90 
The aim is to understand the frequency of 90 in 575921.

Advancing to step 1:
90 can be fit into 5 0 times, resulting in a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Fetch the next digit (7) from the dividend, attach it to 5 and continue: 57 / 90

Advancing to step 2:
90 can be fit into 57 0 times, resulting in a remainder of 57.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 57 after subtracting 0 from 57.
Append the next digit (5) from the dividend to 57 and continue with: 575 / 90

On to step 3:
575 divided by 90 is 6 with a remainder of 35.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
Deduct 540 from 575 and we're left with 35.
Fetch the next digit (9) from the dividend, attach it to 35 and continue: 359 / 90

Step 4:
The number 90 fits into 359 3 times, leaving a remainder of 89.
The next digit of our result is 3. 
Result so far: 63.0
Deduct 270 from 359 and we're left with 89.
Append the next digit (2) from the dividend to 89 and continue with: 892 / 90

Let's proceed to step 5:
The number 90 fits into 892 9 times, leaving a remainder of 82.
The next digit of our result is 9. 
Result so far: 639.0
The remainder is 82 after subtracting 810 from 892.
Append the next digit (1) from the dividend to 82 and continue with: 821 / 90

Advancing to step 6:
The number 90 fits into 821 9 times, leaving a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 6399.0
If we subtract 810 from 821, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 7:
90 can be fit into 110 1 times, resulting in a remainder of 20.
Use 1 as the next digit of our solution. 
Result so far: 6399.1
Subtracting 90 from 110 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 8:
When dividing 200 by 90, we get 2 with a remainder of 20.
Put 2 as the next digit of the answer. 
Result so far: 6399.12
Subtract 180 from 200 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 9:
90 goes into 200 2 times with a remainder of 20.
The number 2 becomes the next digit in our result. 
Result so far: 6399.122
If we take 180 away from 200, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The quotient of the division is 6399.122, and the remainder is 0.002.