We look at the division of 395391 by 42 
The aim is to understand the frequency of 42 in 395391.

On to step 1:
If we divide 3 by 42, we get 0 and a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 42

Going ahead to step 2:
39 divided by 42 is 0 with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 39, we end up with 39.
Grab the next digit (5) from the dividend, add it to 39, then carry on: 395 / 42

Advancing to step 3:
42 goes into 395 9 times with a remainder of 17.
The number 9 becomes the next digit in our result. 
Result so far: 9.0
Subtract 378 from 395 to get 17.
Fetch the next digit (3) from the dividend, attach it to 17 and continue: 173 / 42

On to step 4:
When dividing 173 by 42, we get 4 with a remainder of 5.
The number 4 becomes the next digit in our result. 
Result so far: 94.0
If we take 168 away from 173, we end up with 5.
Include the next digit (9) from the dividend after 5, then repeat: 59 / 42

Advancing to step 5:
42 goes into 59 1 times with a remainder of 17.
The next digit of our result is 1. 
Result so far: 941.0
Deduct 42 from 59 and we're left with 17.
Fetch the next digit (1) from the dividend, attach it to 17 and continue: 171 / 42

Going ahead to step 6:
If we divide 171 by 42, we get 4 and a remainder of 3.
Write down 4 as next digit of the result. 
Result so far: 9414.0
If we subtract 168 from 171, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 7:
The number 42 fits into 30 0 times, leaving a remainder of 30.
Put 0 as the next digit of the answer. 
Result so far: 9414.0
If we take 0 away from 30, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

On to step 8:
The number 42 fits into 300 7 times, leaving a remainder of 6.
The next digit of our result is 7. 
Result so far: 9414.07
If we take 294 away from 300, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 9:
42 goes into 60 1 times with a remainder of 18.
Use 1 as the next digit of our solution. 
Result so far: 9414.071
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 10:
180 divided by 42 is 4 with a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 9414.0714
If we subtract 168 from 180, we 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.

Moving on to step 11:
42 goes into 120 2 times with a remainder of 36.
The next digit of our result is 2. 
Result so far: 9414.07142
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.

Let's proceed to step 12:
42 goes into 360 8 times with a remainder of 24.
Write down 8 as next digit of the result. 
Result so far: 9414.071428
If we subtract 336 from 360, we 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.

Advancing to step 13:
If we divide 240 by 42, we get 5 and a remainder of 30.
Record the quotient 5 as the next digit in the result. 
Result so far: 9414.0714285
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.

Moving on to step 14:
42 goes into 300 7 times with a remainder of 6.
Write down 7 as next digit of the result. 
Result so far: 9414.07142857
Deduct 294 from 300 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

After the division, we end up with 9414.07142857 and a remainder of 6e-09.