We're dividing 509205 by 42 
The aim is to understand the frequency of 42 in 509205.

Moving on to step 1:
5 divided by 42 is 0 with a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Take the next digit (0) from the dividend and append it to 5, then repeat: 50 / 42

Let's proceed to step 2:
The number 42 fits into 50 1 times, leaving a remainder of 8.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
The remainder is 8 after subtracting 42 from 50.
Bring next digit (9) of the dividend behind the 8 and repeat the process: 89 / 42

On to step 3:
The number 42 fits into 89 2 times, leaving a remainder of 5.
Use 2 as the next digit of our solution. 
Result so far: 12.0
Deduct 84 from 89 and we're left with 5.
Append the next digit (2) from the dividend to 5 and continue with: 52 / 42

On to step 4:
42 goes into 52 1 times with a remainder of 10.
The next digit of our result is 1. 
Result so far: 121.0
If we subtract 42 from 52, we get 10.
Bring next digit (0) of the dividend behind the 10 and repeat the process: 100 / 42

Step 5:
The number 42 fits into 100 2 times, leaving a remainder of 16.
Write down 2 as next digit of the result. 
Result so far: 1212.0
If we take 84 away from 100, we end up with 16.
Bring next digit (5) of the dividend behind the 16 and repeat the process: 165 / 42

On to step 6:
165 divided by 42 is 3 with a remainder of 39.
The number 3 becomes the next digit in our result. 
Result so far: 12123.0
The remainder is 39 after subtracting 126 from 165.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

On to step 7:
When dividing 390 by 42, we get 9 with a remainder of 12.
The number 9 becomes the next digit in our result. 
Result so far: 12123.9
The remainder is 12 after subtracting 378 from 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 8:
120 divided by 42 is 2 with a remainder of 36.
Record the quotient 2 as the next digit in the result. 
Result so far: 12123.92
Deduct 84 from 120 and we're left with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Let's proceed to step 9:
The number 42 fits into 360 8 times, leaving a remainder of 24.
The next digit of our result is 8. 
Result so far: 12123.928
Subtract 336 from 360 to get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Step 10:
The number 42 fits into 240 5 times, leaving a remainder of 30.
Write down 5 as next digit of the result. 
Result so far: 12123.9285
Subtract 210 from 240 to get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Let's proceed to step 11:
When dividing 300 by 42, we get 7 with a remainder of 6.
The next digit of our result is 7. 
Result so far: 12123.92857
The remainder is 6 after subtracting 294 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 12:
The number 42 fits into 60 1 times, leaving a remainder of 18.
Record the quotient 1 as the next digit in the result. 
Result so far: 12123.928571
If we take 42 away from 60, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 13:
42 can be fit into 180 4 times, resulting in a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 12123.9285714
Subtract 168 from 180 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.

Advancing to step 14:
The number 42 fits into 120 2 times, leaving a remainder of 36.
The number 2 becomes the next digit in our result. 
Result so far: 12123.92857142
If we subtract 84 from 120, we get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

After the division, we end up with 12123.92857142 and a remainder of 3.6e-08.