We're dividing 393957 by 42 
We want to figure out the number of times 393957 can be divided by 42.

Advancing to step 1:
42 can be fit into 3 0 times, resulting in a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 42

Let's proceed to step 2:
If we divide 39 by 42, we get 0 and a remainder of 39.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 39 and we're left with 39.
Grab the next digit (3) from the dividend, add it to 39, then carry on: 393 / 42

Let's proceed to step 3:
393 divided by 42 is 9 with a remainder of 15.
The next digit of our result is 9. 
Result so far: 9.0
If we subtract 378 from 393, we get 15.
Append the next digit (9) from the dividend to 15 and continue with: 159 / 42

Let's proceed to step 4:
42 can be fit into 159 3 times, resulting in a remainder of 33.
Write down 3 as next digit of the result. 
Result so far: 93.0
If we take 126 away from 159, we end up with 33.
Grab the next digit (5) from the dividend, add it to 33, then carry on: 335 / 42

Step 5:
42 goes into 335 7 times with a remainder of 41.
Put 7 as the next digit of the answer. 
Result so far: 937.0
Subtracting 294 from 335 leaves us with 41.
Fetch the next digit (7) from the dividend, attach it to 41 and continue: 417 / 42

Advancing to step 6:
The number 42 fits into 417 9 times, leaving a remainder of 39.
The number 9 becomes the next digit in our result. 
Result so far: 9379.0
Subtracting 378 from 417 leaves us with 39.
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:
390 divided by 42 is 9 with a remainder of 12.
Use 9 as the next digit of our solution. 
Result so far: 9379.9
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.

On to step 8:
42 goes into 120 2 times with a remainder of 36.
Write down 2 as next digit of the result. 
Result so far: 9379.92
The remainder is 36 after subtracting 84 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

On to step 9:
360 divided by 42 is 8 with a remainder of 24.
The next digit of our result is 8. 
Result so far: 9379.928
The remainder is 24 after subtracting 336 from 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Going ahead to step 10:
If we divide 240 by 42, we get 5 and a remainder of 30.
Use 5 as the next digit of our solution. 
Result so far: 9379.9285
If we subtract 210 from 240, we 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.

Step 11:
If we divide 300 by 42, we get 7 and a remainder of 6.
Record the quotient 7 as the next digit in the result. 
Result so far: 9379.92857
Subtract 294 from 300 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 12:
If we divide 60 by 42, we get 1 and a remainder of 18.
Use 1 as the next digit of our solution. 
Result so far: 9379.928571
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.

Let's proceed to step 13:
If we divide 180 by 42, we get 4 and a remainder of 12.
Put 4 as the next digit of the answer. 
Result so far: 9379.9285714
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.

Let's proceed to step 14:
If we divide 120 by 42, we get 2 and a remainder of 36.
Write down 2 as next digit of the result. 
Result so far: 9379.92857142
The remainder is 36 after subtracting 84 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

The final outcome is 9379.92857142, with a leftover of 3.6e-08.