517951 divided by 42 
The aim is to understand the frequency of 42 in 517951.

Step 1:
5 divided by 42 is 0 with a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 42

On to step 2:
The number 42 fits into 51 1 times, leaving a remainder of 9.
The next digit of our result is 1. 
Result so far: 1.0
If we take 42 away from 51, we end up with 9.
Bring next digit (7) of the dividend behind the 9 and repeat the process: 97 / 42

Going ahead to step 3:
If we divide 97 by 42, we get 2 and a remainder of 13.
The next digit of our result is 2. 
Result so far: 12.0
Deduct 84 from 97 and we're left with 13.
Take the next digit (9) from the dividend and append it to 13, then repeat: 139 / 42

Moving on to step 4:
When dividing 139 by 42, we get 3 with a remainder of 13.
The number 3 becomes the next digit in our result. 
Result so far: 123.0
Deduct 126 from 139 and we're left with 13.
Take the next digit (5) from the dividend and append it to 13, then repeat: 135 / 42

Advancing to step 5:
42 goes into 135 3 times with a remainder of 9.
Use 3 as the next digit of our solution. 
Result so far: 1233.0
Subtract 126 from 135 to get 9.
Take the next digit (1) from the dividend and append it to 9, then repeat: 91 / 42

Going ahead to step 6:
42 goes into 91 2 times with a remainder of 7.
Record the quotient 2 as the next digit in the result. 
Result so far: 12332.0
Subtracting 84 from 91 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 7:
70 divided by 42 is 1 with a remainder of 28.
Write down 1 as next digit of the result. 
Result so far: 12332.1
The remainder is 28 after subtracting 42 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Advancing to step 8:
42 goes into 280 6 times with a remainder of 28.
The next digit of our result is 6. 
Result so far: 12332.16
If we subtract 252 from 280, we get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Let's proceed to step 9:
The number 42 fits into 280 6 times, leaving a remainder of 28.
Put 6 as the next digit of the answer. 
Result so far: 12332.166
Subtract 252 from 280 to get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Our division results in 12332.166 with a remaining 0.0028.