We look at the division of 990691 by 18 
The aim is to understand the frequency of 18 in 990691.

Step 1:
18 goes into 9 0 times with a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Include the next digit (9) from the dividend after 9, then repeat: 99 / 18

Step 2:
When dividing 99 by 18, we get 5 with a remainder of 9.
Write down 5 as next digit of the result. 
Result so far: 5.0
The remainder is 9 after subtracting 90 from 99.
Fetch the next digit (0) from the dividend, attach it to 9 and continue: 90 / 18

Moving on to step 3:
90 divided by 18 is 5 with a remainder of 0.
Write down 5 as next digit of the result. 
Result so far: 55.0
Subtract 90 from 90 to get 0.
Grab the next digit (6) from the dividend, add it to 0, then carry on: 6 / 18

Step 4:
If we divide 6 by 18, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 550.0
Subtract 0 from 6 to get 6.
Fetch the next digit (9) from the dividend, attach it to 6 and continue: 69 / 18

Moving on to step 5:
If we divide 69 by 18, we get 3 and a remainder of 15.
Write down 3 as next digit of the result. 
Result so far: 5503.0
Subtract 54 from 69 to get 15.
Fetch the next digit (1) from the dividend, attach it to 15 and continue: 151 / 18

Advancing to step 6:
If we divide 151 by 18, we get 8 and a remainder of 7.
Write down 8 as next digit of the result. 
Result so far: 55038.0
The remainder is 7 after subtracting 144 from 151.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 7:
The number 18 fits into 70 3 times, leaving a remainder of 16.
Record the quotient 3 as the next digit in the result. 
Result so far: 55038.3
The remainder is 16 after subtracting 54 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 8:
160 divided by 18 is 8 with a remainder of 16.
Put 8 as the next digit of the answer. 
Result so far: 55038.38
If we take 144 away from 160, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 9:
When dividing 160 by 18, we get 8 with a remainder of 16.
Use 8 as the next digit of our solution. 
Result so far: 55038.388
Subtracting 144 from 160 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

In conclusion, the division gives 55038.388 with a balance of 0.0016.