660558 ÷ 9 
The aim is to understand the frequency of 9 in 660558.

Let's proceed to step 1:
If we divide 6 by 9, we get 0 and a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Take the next digit (6) from the dividend and append it to 6, then repeat: 66 / 9

Let's proceed to step 2:
If we divide 66 by 9, we get 7 and a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 7.0
If we subtract 63 from 66, we get 3.
Grab the next digit (0) from the dividend, add it to 3, then carry on: 30 / 9

Advancing to step 3:
If we divide 30 by 9, we get 3 and a remainder of 3.
Use 3 as the next digit of our solution. 
Result so far: 73.0
The remainder is 3 after subtracting 27 from 30.
Take the next digit (5) from the dividend and append it to 3, then repeat: 35 / 9

Let's proceed to step 4:
9 goes into 35 3 times with a remainder of 8.
Write down 3 as next digit of the result. 
Result so far: 733.0
The remainder is 8 after subtracting 27 from 35.
Include the next digit (5) from the dividend after 8, then repeat: 85 / 9

Let's proceed to step 5:
85 divided by 9 is 9 with a remainder of 4.
Write down 9 as next digit of the result. 
Result so far: 7339.0
Deduct 81 from 85 and we're left with 4.
Fetch the next digit (8) from the dividend, attach it to 4 and continue: 48 / 9

On to step 6:
If we divide 48 by 9, we get 5 and a remainder of 3.
The number 5 becomes the next digit in our result. 
Result so far: 73395.0
Deduct 45 from 48 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 7:
30 divided by 9 is 3 with a remainder of 3.
The next digit of our result is 3. 
Result so far: 73395.3
Subtract 27 from 30 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 8:
30 divided by 9 is 3 with a remainder of 3.
Use 3 as the next digit of our solution. 
Result so far: 73395.33
Subtract 27 from 30 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

The final outcome is 73395.33, with a leftover of 0.003.