We look at the division of 399608 by 15 
We want to figure out the number of times 399608 can be divided by 15.

Advancing to step 1:
If we divide 3 by 15, we get 0 and a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 15

Advancing to step 2:
If we divide 39 by 15, we get 2 and a remainder of 9.
Put 2 as the next digit of the answer. 
Result so far: 2.0
If we subtract 30 from 39, we get 9.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 15

Going ahead to step 3:
99 divided by 15 is 6 with a remainder of 9.
Write down 6 as next digit of the result. 
Result so far: 26.0
Deduct 90 from 99 and we're left with 9.
Append the next digit (6) from the dividend to 9 and continue with: 96 / 15

On to step 4:
15 goes into 96 6 times with a remainder of 6.
Write down 6 as next digit of the result. 
Result so far: 266.0
Subtracting 90 from 96 leaves us with 6.
Bring next digit (0) of the dividend behind the 6 and repeat the process: 60 / 15

Advancing to step 5:
15 goes into 60 4 times with a remainder of 0.
Record the quotient 4 as the next digit in the result. 
Result so far: 2664.0
If we subtract 60 from 60, we get 0.
Include the next digit (8) from the dividend after 0, then repeat: 8 / 15

Moving on to step 6:
8 divided by 15 is 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 26640.0
Deduct 0 from 8 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 7:
15 goes into 80 5 times with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 26640.5
The remainder is 5 after subtracting 75 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 8:
When dividing 50 by 15, we get 3 with a remainder of 5.
The next digit of our result is 3. 
Result so far: 26640.53
If we subtract 45 from 50, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 9:
50 divided by 15 is 3 with a remainder of 5.
The number 3 becomes the next digit in our result. 
Result so far: 26640.533
Subtract 45 from 50 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

The final result is 26640.533 with a remainder of 0.0005.