We're dividing 660218 by 90 
The aim is to understand the frequency of 90 in 660218.

Moving on to step 1:
When dividing 6 by 90, we get 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Grab the next digit (6) from the dividend, add it to 6, then carry on: 66 / 90

Step 2:
The number 90 fits into 66 0 times, leaving a remainder of 66.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 66 leaves us with 66.
Include the next digit (0) from the dividend after 66, then repeat: 660 / 90

On to step 3:
660 divided by 90 is 7 with a remainder of 30.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
If we take 630 away from 660, we end up with 30.
Append the next digit (2) from the dividend to 30 and continue with: 302 / 90

Step 4:
302 divided by 90 is 3 with a remainder of 32.
Put 3 as the next digit of the answer. 
Result so far: 73.0
If we subtract 270 from 302, we get 32.
Bring next digit (1) of the dividend behind the 32 and repeat the process: 321 / 90

Moving on to step 5:
321 divided by 90 is 3 with a remainder of 51.
Write down 3 as next digit of the result. 
Result so far: 733.0
If we subtract 270 from 321, we get 51.
Include the next digit (8) from the dividend after 51, then repeat: 518 / 90

On to step 6:
90 goes into 518 5 times with a remainder of 68.
The next digit of our result is 5. 
Result so far: 7335.0
The remainder is 68 after subtracting 450 from 518.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Going ahead to step 7:
90 can be fit into 680 7 times, resulting in a remainder of 50.
Record the quotient 7 as the next digit in the result. 
Result so far: 7335.7
Deduct 630 from 680 and we're left with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

On to step 8:
90 goes into 500 5 times with a remainder of 50.
The number 5 becomes the next digit in our result. 
Result so far: 7335.75
If we subtract 450 from 500, we get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 9:
If we divide 500 by 90, we get 5 and a remainder of 50.
Put 5 as the next digit of the answer. 
Result so far: 7335.755
The remainder is 50 after subtracting 450 from 500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Our division results in 7335.755 with a remaining 0.005.