We look at the division of 548425 by 18 
The aim is to understand the frequency of 18 in 548425.

Let's proceed to step 1:
When dividing 5 by 18, we get 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Take the next digit (4) from the dividend and append it to 5, then repeat: 54 / 18

Going ahead to step 2:
If we divide 54 by 18, we get 3 and a remainder of 0.
Use 3 as the next digit of our solution. 
Result so far: 3.0
The remainder is 0 after subtracting 54 from 54.
Take the next digit (8) from the dividend and append it to 0, then repeat: 8 / 18

Moving on to step 3:
8 divided by 18 is 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 30.0
Subtract 0 from 8 to get 8.
Bring next digit (4) of the dividend behind the 8 and repeat the process: 84 / 18

Step 4:
The number 18 fits into 84 4 times, leaving a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 304.0
If we subtract 72 from 84, we get 12.
Append the next digit (2) from the dividend to 12 and continue with: 122 / 18

Going ahead to step 5:
When dividing 122 by 18, we get 6 with a remainder of 14.
The next digit of our result is 6. 
Result so far: 3046.0
Deduct 108 from 122 and we're left with 14.
Fetch the next digit (5) from the dividend, attach it to 14 and continue: 145 / 18

On to step 6:
18 goes into 145 8 times with a remainder of 1.
The number 8 becomes the next digit in our result. 
Result so far: 30468.0
If we subtract 144 from 145, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 7:
If we divide 10 by 18, we get 0 and a remainder of 10.
The next digit of our result is 0. 
Result so far: 30468.0
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 8:
If we divide 100 by 18, we get 5 and a remainder of 10.
Use 5 as the next digit of our solution. 
Result so far: 30468.05
If we take 90 away from 100, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 9:
100 divided by 18 is 5 with a remainder of 10.
The next digit of our result is 5. 
Result so far: 30468.055
If we subtract 90 from 100, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final outcome is 30468.055, with a leftover of 0.001.