Let's divide 399315 by 15
We want to figure out the number of times 399315 can be divided by 15.

Let's proceed to step 1:
The number 15 fits into 3 0 times, leaving a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 15

Moving on to step 2:
39 divided by 15 is 2 with a remainder of 9.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Subtracting 30 from 39 leaves us with 9.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 15

Advancing to step 3:
When dividing 99 by 15, we get 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 (3) from the dividend to 9 and continue with: 93 / 15

On to step 4:
If we divide 93 by 15, we get 6 and a remainder of 3.
Put 6 as the next digit of the answer. 
Result so far: 266.0
If we subtract 90 from 93, we get 3.
Include the next digit (1) from the dividend after 3, then repeat: 31 / 15

Step 5:
When dividing 31 by 15, we get 2 with a remainder of 1.
Put 2 as the next digit of the answer. 
Result so far: 2662.0
If we subtract 30 from 31, we get 1.
Fetch the next digit (5) from the dividend, attach it to 1 and continue: 15 / 15

Going ahead to step 6:
When dividing 15 by 15, we get 1 with a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 26621.0
The remainder is 0 after subtracting 15 from 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 7:
When dividing 0 by 15, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 26621.0
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 8:
The number 15 fits into 0 0 times, leaving a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 26621.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 26621.0, with a leftover of 0.0.