Let's divide 435090 by 18
The aim is to understand the frequency of 18 in 435090.

On to step 1:
18 goes into 4 0 times with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Append the next digit (3) from the dividend to 4 and continue with: 43 / 18

Advancing to step 2:
If we divide 43 by 18, we get 2 and a remainder of 7.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Deduct 36 from 43 and we're left with 7.
Append the next digit (5) from the dividend to 7 and continue with: 75 / 18

On to step 3:
The number 18 fits into 75 4 times, leaving a remainder of 3.
Use 4 as the next digit of our solution. 
Result so far: 24.0
The remainder is 3 after subtracting 72 from 75.
Append the next digit (0) from the dividend to 3 and continue with: 30 / 18

Going ahead to step 4:
18 goes into 30 1 times with a remainder of 12.
Record the quotient 1 as the next digit in the result. 
Result so far: 241.0
If we subtract 18 from 30, we get 12.
Include the next digit (9) from the dividend after 12, then repeat: 129 / 18

Step 5:
The number 18 fits into 129 7 times, leaving a remainder of 3.
The next digit of our result is 7. 
Result so far: 2417.0
The remainder is 3 after subtracting 126 from 129.
Include the next digit (0) from the dividend after 3, then repeat: 30 / 18

Going ahead to step 6:
30 divided by 18 is 1 with a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 24171.0
Subtract 18 from 30 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.

On to step 7:
120 divided by 18 is 6 with a remainder of 12.
Put 6 as the next digit of the answer. 
Result so far: 24171.6
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.

Let's proceed to step 8:
If we divide 120 by 18, we get 6 and a remainder of 12.
Record the quotient 6 as the next digit in the result. 
Result so far: 24171.66
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 24171.66 and a remainder of 0.012.