We look at the division of 627591 by 18 
The aim is to understand the frequency of 18 in 627591.

Advancing to step 1:
The number 18 fits into 6 0 times, leaving a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Fetch the next digit (2) from the dividend, attach it to 6 and continue: 62 / 18

Moving on to step 2:
The number 18 fits into 62 3 times, leaving a remainder of 8.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtract 54 from 62 to get 8.
Append the next digit (7) from the dividend to 8 and continue with: 87 / 18

Going ahead to step 3:
87 divided by 18 is 4 with a remainder of 15.
Record the quotient 4 as the next digit in the result. 
Result so far: 34.0
Subtract 72 from 87 to get 15.
Fetch the next digit (5) from the dividend, attach it to 15 and continue: 155 / 18

On to step 4:
18 goes into 155 8 times with a remainder of 11.
The number 8 becomes the next digit in our result. 
Result so far: 348.0
If we subtract 144 from 155, we get 11.
Grab the next digit (9) from the dividend, add it to 11, then carry on: 119 / 18

Advancing to step 5:
When dividing 119 by 18, we get 6 with a remainder of 11.
The number 6 becomes the next digit in our result. 
Result so far: 3486.0
Subtract 108 from 119 to get 11.
Bring next digit (1) of the dividend behind the 11 and repeat the process: 111 / 18

Step 6:
When dividing 111 by 18, we get 6 with a remainder of 3.
The next digit of our result is 6. 
Result so far: 34866.0
If we subtract 108 from 111, we 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.

On to step 7:
If we divide 30 by 18, we get 1 and a remainder of 12.
Write down 1 as next digit of the result. 
Result so far: 34866.1
Subtracting 18 from 30 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 8:
120 divided by 18 is 6 with a remainder of 12.
Record the quotient 6 as the next digit in the result. 
Result so far: 34866.16
Deduct 108 from 120 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 9:
When dividing 120 by 18, we get 6 with a remainder of 12.
The next digit of our result is 6. 
Result so far: 34866.166
If we take 108 away from 120, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Our division results in 34866.166 with a remaining 0.0012.