258399 ÷ 15 
Let's see how many times 15 fits into 258399.

Step 1:
15 can be fit into 2 0 times, resulting in a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Fetch the next digit (5) from the dividend, attach it to 2 and continue: 25 / 15

Let's proceed to step 2:
If we divide 25 by 15, we get 1 and a remainder of 10.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 15 away from 25, we end up with 10.
Grab the next digit (8) from the dividend, add it to 10, then carry on: 108 / 15

Going ahead to step 3:
108 divided by 15 is 7 with a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 17.0
If we take 105 away from 108, we end up with 3.
Take the next digit (3) from the dividend and append it to 3, then repeat: 33 / 15

Advancing to step 4:
The number 15 fits into 33 2 times, leaving a remainder of 3.
Put 2 as the next digit of the answer. 
Result so far: 172.0
If we take 30 away from 33, we end up with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 15

Going ahead to step 5:
When dividing 39 by 15, we get 2 with a remainder of 9.
The number 2 becomes the next digit in our result. 
Result so far: 1722.0
The remainder is 9 after subtracting 30 from 39.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 15

Advancing to step 6:
If we divide 99 by 15, we get 6 and a remainder of 9.
Use 6 as the next digit of our solution. 
Result so far: 17226.0
Subtract 90 from 99 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 7:
15 can be fit into 90 6 times, resulting in a remainder of 0.
The next digit of our result is 6. 
Result so far: 17226.6
The remainder is 0 after subtracting 90 from 90.
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 8:
15 can be fit into 0 0 times, resulting in a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 17226.6
Subtracting 0 from 0 leaves us 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.

On to step 9:
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: 17226.6
Subtracting 0 from 0 leaves us 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 quotient of the division is 17226.6, and the remainder is 0.0.