We look at the division of 400939 by 18 
We're looking to find how many times 18 goes into 400939.

Let's proceed to step 1:
18 can be fit into 4 0 times, resulting in a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Take the next digit (0) from the dividend and append it to 4, then repeat: 40 / 18

Let's proceed to step 2:
The number 18 fits into 40 2 times, leaving a remainder of 4.
Put 2 as the next digit of the answer. 
Result so far: 2.0
If we take 36 away from 40, we end up with 4.
Take the next digit (0) from the dividend and append it to 4, then repeat: 40 / 18

Going ahead to step 3:
40 divided by 18 is 2 with a remainder of 4.
Use 2 as the next digit of our solution. 
Result so far: 22.0
Subtracting 36 from 40 leaves us with 4.
Take the next digit (9) from the dividend and append it to 4, then repeat: 49 / 18

Going ahead to step 4:
18 can be fit into 49 2 times, resulting in a remainder of 13.
The next digit of our result is 2. 
Result so far: 222.0
Subtracting 36 from 49 leaves us with 13.
Append the next digit (3) from the dividend to 13 and continue with: 133 / 18

Step 5:
If we divide 133 by 18, we get 7 and a remainder of 7.
The next digit of our result is 7. 
Result so far: 2227.0
Subtracting 126 from 133 leaves us with 7.
Bring next digit (9) of the dividend behind the 7 and repeat the process: 79 / 18

Step 6:
18 can be fit into 79 4 times, resulting in a remainder of 7.
The number 4 becomes the next digit in our result. 
Result so far: 22274.0
If we subtract 72 from 79, we get 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:
When dividing 70 by 18, we get 3 with a remainder of 16.
Use 3 as the next digit of our solution. 
Result so far: 22274.3
Deduct 54 from 70 and we're left with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 8:
If we divide 160 by 18, we get 8 and a remainder of 16.
Write down 8 as next digit of the result. 
Result so far: 22274.38
If we take 144 away from 160, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 9:
When dividing 160 by 18, we get 8 with a remainder of 16.
Write down 8 as next digit of the result. 
Result so far: 22274.388
Subtract 144 from 160 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The final result is 22274.388 with a remainder of 0.0016.