Let's divide 40668 by 90
The aim is to understand the frequency of 90 in 40668.

Step 1:
The number 90 fits into 4 0 times, leaving a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 90

On to step 2:
The number 90 fits into 40 0 times, leaving a remainder of 40.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 40, we end up with 40.
Bring next digit (6) of the dividend behind the 40 and repeat the process: 406 / 90

Moving on to step 3:
The number 90 fits into 406 4 times, leaving a remainder of 46.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we take 360 away from 406, we end up with 46.
Include the next digit (6) from the dividend after 46, then repeat: 466 / 90

Step 4:
90 can be fit into 466 5 times, resulting in a remainder of 16.
Record the quotient 5 as the next digit in the result. 
Result so far: 45.0
If we take 450 away from 466, we end up with 16.
Include the next digit (8) from the dividend after 16, then repeat: 168 / 90

On to step 5:
If we divide 168 by 90, we get 1 and a remainder of 78.
Write down 1 as next digit of the result. 
Result so far: 451.0
If we take 90 away from 168, we end up with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Going ahead to step 6:
When dividing 780 by 90, we get 8 with a remainder of 60.
The number 8 becomes the next digit in our result. 
Result so far: 451.8
Subtracting 720 from 780 leaves us 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.

Let's proceed to step 7:
The number 90 fits into 600 6 times, leaving a remainder of 60.
Record the quotient 6 as the next digit in the result. 
Result so far: 451.86
If we subtract 540 from 600, we 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 8:
90 can be fit into 600 6 times, resulting in a remainder of 60.
The next digit of our result is 6. 
Result so far: 451.866
Subtract 540 from 600 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.

After the division, we end up with 451.866 and a remainder of 0.006.