We look at the division of 239646 by 18 
The aim is to understand the frequency of 18 in 239646.

Step 1:
The number 18 fits into 2 0 times, leaving a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Take the next digit (3) from the dividend and append it to 2, then repeat: 23 / 18

Going ahead to step 2:
18 can be fit into 23 1 times, resulting in a remainder of 5.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 18 from 23 and we're left with 5.
Bring next digit (9) of the dividend behind the 5 and repeat the process: 59 / 18

Let's proceed to step 3:
18 goes into 59 3 times with a remainder of 5.
Put 3 as the next digit of the answer. 
Result so far: 13.0
If we subtract 54 from 59, we get 5.
Grab the next digit (6) from the dividend, add it to 5, then carry on: 56 / 18

Let's proceed to step 4:
56 divided by 18 is 3 with a remainder of 2.
Put 3 as the next digit of the answer. 
Result so far: 133.0
If we take 54 away from 56, we end up with 2.
Take the next digit (4) from the dividend and append it to 2, then repeat: 24 / 18

Let's proceed to step 5:
When dividing 24 by 18, we get 1 with a remainder of 6.
The number 1 becomes the next digit in our result. 
Result so far: 1331.0
Deduct 18 from 24 and we're left with 6.
Bring next digit (6) of the dividend behind the 6 and repeat the process: 66 / 18

Let's proceed to step 6:
18 can be fit into 66 3 times, resulting in a remainder of 12.
Write down 3 as next digit of the result. 
Result so far: 13313.0
The remainder is 12 after subtracting 54 from 66.
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 7:
The number 18 fits into 120 6 times, leaving a remainder of 12.
The next digit of our result is 6. 
Result so far: 13313.6
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.

Let's proceed to step 8:
120 divided by 18 is 6 with a remainder of 12.
Write down 6 as next digit of the result. 
Result so far: 13313.66
Subtract 108 from 120 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

After the division, we end up with 13313.66 and a remainder of 0.012.