390408 divided by 18 
Let's see how many times 18 fits into 390408.

Let's proceed to step 1:
If we divide 3 by 18, we get 0 and a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 18

Let's proceed to step 2:
18 can be fit into 39 2 times, resulting in a remainder of 3.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
If we take 36 away from 39, we end up with 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 18

Let's proceed to step 3:
If we divide 30 by 18, we get 1 and a remainder of 12.
Put 1 as the next digit of the answer. 
Result so far: 21.0
The remainder is 12 after subtracting 18 from 30.
Bring next digit (4) of the dividend behind the 12 and repeat the process: 124 / 18

Let's proceed to step 4:
18 can be fit into 124 6 times, resulting in a remainder of 16.
Record the quotient 6 as the next digit in the result. 
Result so far: 216.0
The remainder is 16 after subtracting 108 from 124.
Grab the next digit (0) from the dividend, add it to 16, then carry on: 160 / 18

Step 5:
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: 2168.0
Subtracting 144 from 160 leaves us with 16.
Take the next digit (8) from the dividend and append it to 16, then repeat: 168 / 18

Going ahead to step 6:
When dividing 168 by 18, we get 9 with a remainder of 6.
Put 9 as the next digit of the answer. 
Result so far: 21689.0
Subtract 162 from 168 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.

Moving on to step 7:
18 can be fit into 60 3 times, resulting in a remainder of 6.
The number 3 becomes the next digit in our result. 
Result so far: 21689.3
If we take 54 away from 60, 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.

Going ahead to step 8:
If we divide 60 by 18, we get 3 and a remainder of 6.
The next digit of our result is 3. 
Result so far: 21689.33
Subtract 54 from 60 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.

In conclusion, the division gives 21689.33 with a balance of 0.006.