We look at the division of 664370 by 18 
The aim is to understand the frequency of 18 in 664370.

Advancing to step 1:
18 can be fit into 6 0 times, resulting in 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.
Append the next digit (6) from the dividend to 6 and continue with: 66 / 18

Moving on to step 2:
If we divide 66 by 18, we get 3 and a remainder of 12.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Subtract 54 from 66 to get 12.
Include the next digit (4) from the dividend after 12, then repeat: 124 / 18

Step 3:
The number 18 fits into 124 6 times, leaving a remainder of 16.
Put 6 as the next digit of the answer. 
Result so far: 36.0
The remainder is 16 after subtracting 108 from 124.
Append the next digit (3) from the dividend to 16 and continue with: 163 / 18

Advancing to step 4:
163 divided by 18 is 9 with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 369.0
If we take 162 away from 163, we end up with 1.
Take the next digit (7) from the dividend and append it to 1, then repeat: 17 / 18

On to step 5:
The number 18 fits into 17 0 times, leaving a remainder of 17.
The number 0 becomes the next digit in our result. 
Result so far: 3690.0
Subtract 0 from 17 to get 17.
Fetch the next digit (0) from the dividend, attach it to 17 and continue: 170 / 18

Step 6:
The number 18 fits into 170 9 times, leaving a remainder of 8.
Use 9 as the next digit of our solution. 
Result so far: 36909.0
Subtracting 162 from 170 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 7:
When dividing 80 by 18, we get 4 with a remainder of 8.
Write down 4 as next digit of the result. 
Result so far: 36909.4
If we take 72 away from 80, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 8:
The number 18 fits into 80 4 times, leaving a remainder of 8.
The next digit of our result is 4. 
Result so far: 36909.44
Subtract 72 from 80 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

After the division, we end up with 36909.44 and a remainder of 0.008.