We look at the division of 42397443 by 831 
Let's see how many times 831 fits into 42397443.

Advancing to step 1:
When dividing 4 by 831, we get 0 with a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Grab the next digit (2) from the dividend, add it to 4, then carry on: 42 / 831

Step 2:
831 goes into 42 0 times with a remainder of 42.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 42, we get 42.
Append the next digit (3) from the dividend to 42 and continue with: 423 / 831

Moving on to step 3:
When dividing 423 by 831, we get 0 with a remainder of 423.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 423 to get 423.
Take the next digit (9) from the dividend and append it to 423, then repeat: 4239 / 831

On to step 4:
The number 831 fits into 4239 5 times, leaving a remainder of 84.
Write down 5 as next digit of the result. 
Result so far: 5.0
Deduct 4155 from 4239 and we're left with 84.
Grab the next digit (7) from the dividend, add it to 84, then carry on: 847 / 831

Moving on to step 5:
If we divide 847 by 831, we get 1 and a remainder of 16.
Write down 1 as next digit of the result. 
Result so far: 51.0
Deduct 831 from 847 and we're left with 16.
Include the next digit (4) from the dividend after 16, then repeat: 164 / 831

Going ahead to step 6:
If we divide 164 by 831, we get 0 and a remainder of 164.
Write down 0 as next digit of the result. 
Result so far: 510.0
Subtract 0 from 164 to get 164.
Append the next digit (4) from the dividend to 164 and continue with: 1644 / 831

Advancing to step 7:
1644 divided by 831 is 1 with a remainder of 813.
Record the quotient 1 as the next digit in the result. 
Result so far: 5101.0
Subtract 831 from 1644 to get 813.
Include the next digit (3) from the dividend after 813, then repeat: 8133 / 831

Step 8:
831 can be fit into 8133 9 times, resulting in a remainder of 654.
The next digit of our result is 9. 
Result so far: 51019.0
Deduct 7479 from 8133 and we're left with 654.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6540, and continue the process.

Step 9:
6540 divided by 831 is 7 with a remainder of 723.
Record the quotient 7 as the next digit in the result. 
Result so far: 51019.7
If we subtract 5817 from 6540, we get 723.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7230, and continue the process.

Going ahead to step 10:
7230 divided by 831 is 8 with a remainder of 582.
Use 8 as the next digit of our solution. 
Result so far: 51019.78
Deduct 6648 from 7230 and we're left with 582.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5820, and continue the process.

Let's proceed to step 11:
831 goes into 5820 7 times with a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 51019.787
If we take 5817 away from 5820, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 12:
831 can be fit into 30 0 times, resulting in a remainder of 30.
Use 0 as the next digit of our solution. 
Result so far: 51019.787
Subtract 0 from 30 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.

On to step 13:
If we divide 300 by 831, we get 0 and a remainder of 300.
The next digit of our result is 0. 
Result so far: 51019.787
Deduct 0 from 300 and we're left with 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

The final outcome is 51019.787, with a leftover of 0.0003.