We look at the division of 15508681 by 864 
Let's see how many times 864 fits into 15508681.

Moving on to step 1:
The number 864 fits into 1 0 times, leaving a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Fetch the next digit (5) from the dividend, attach it to 1 and continue: 15 / 864

On to step 2:
If we divide 15 by 864, we get 0 and a remainder of 15.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 15, we get 15.
Take the next digit (5) from the dividend and append it to 15, then repeat: 155 / 864

Let's proceed to step 3:
If we divide 155 by 864, we get 0 and a remainder of 155.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 155, we end up with 155.
Append the next digit (0) from the dividend to 155 and continue with: 1550 / 864

Advancing to step 4:
The number 864 fits into 1550 1 times, leaving a remainder of 686.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtract 864 from 1550 to get 686.
Append the next digit (8) from the dividend to 686 and continue with: 6868 / 864

Step 5:
6868 divided by 864 is 7 with a remainder of 820.
The number 7 becomes the next digit in our result. 
Result so far: 17.0
Subtract 6048 from 6868 to get 820.
Append the next digit (6) from the dividend to 820 and continue with: 8206 / 864

Advancing to step 6:
8206 divided by 864 is 9 with a remainder of 430.
Put 9 as the next digit of the answer. 
Result so far: 179.0
Subtracting 7776 from 8206 leaves us with 430.
Fetch the next digit (8) from the dividend, attach it to 430 and continue: 4308 / 864

Going ahead to step 7:
864 can be fit into 4308 4 times, resulting in a remainder of 852.
The next digit of our result is 4. 
Result so far: 1794.0
Subtracting 3456 from 4308 leaves us with 852.
Append the next digit (1) from the dividend to 852 and continue with: 8521 / 864

Advancing to step 8:
When dividing 8521 by 864, we get 9 with a remainder of 745.
The next digit of our result is 9. 
Result so far: 17949.0
If we subtract 7776 from 8521, we get 745.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7450, and continue the process.

Moving on to step 9:
7450 divided by 864 is 8 with a remainder of 538.
The number 8 becomes the next digit in our result. 
Result so far: 17949.8
Deduct 6912 from 7450 and we're left with 538.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5380, and continue the process.

On to step 10:
5380 divided by 864 is 6 with a remainder of 196.
Use 6 as the next digit of our solution. 
Result so far: 17949.86
If we take 5184 away from 5380, we end up with 196.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1960, and continue the process.

Advancing to step 11:
864 can be fit into 1960 2 times, resulting in a remainder of 232.
Use 2 as the next digit of our solution. 
Result so far: 17949.862
Subtract 1728 from 1960 to get 232.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2320, and continue the process.

On to step 12:
864 can be fit into 2320 2 times, resulting in a remainder of 592.
The next digit of our result is 2. 
Result so far: 17949.8622
Deduct 1728 from 2320 and we're left with 592.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5920, and continue the process.

The final outcome is 17949.8622, with a leftover of 0.00592.