12583559 divided by 660 
Let's see how many times 660 fits into 12583559.

Moving on to step 1:
The number 660 fits into 1 0 times, leaving a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Append the next digit (2) from the dividend to 1 and continue with: 12 / 660

Going ahead to step 2:
660 can be fit into 12 0 times, resulting in a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Include the next digit (5) from the dividend after 12, then repeat: 125 / 660

Going ahead to step 3:
660 goes into 125 0 times with a remainder of 125.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 125, we end up with 125.
Fetch the next digit (8) from the dividend, attach it to 125 and continue: 1258 / 660

Going ahead to step 4:
1258 divided by 660 is 1 with a remainder of 598.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 660 from 1258 leaves us with 598.
Fetch the next digit (3) from the dividend, attach it to 598 and continue: 5983 / 660

Advancing to step 5:
5983 divided by 660 is 9 with a remainder of 43.
The number 9 becomes the next digit in our result. 
Result so far: 19.0
If we subtract 5940 from 5983, we get 43.
Bring next digit (5) of the dividend behind the 43 and repeat the process: 435 / 660

Moving on to step 6:
435 divided by 660 is 0 with a remainder of 435.
The next digit of our result is 0. 
Result so far: 190.0
The remainder is 435 after subtracting 0 from 435.
Bring next digit (5) of the dividend behind the 435 and repeat the process: 4355 / 660

Moving on to step 7:
The number 660 fits into 4355 6 times, leaving a remainder of 395.
The number 6 becomes the next digit in our result. 
Result so far: 1906.0
Subtracting 3960 from 4355 leaves us with 395.
Bring next digit (9) of the dividend behind the 395 and repeat the process: 3959 / 660

On to step 8:
660 can be fit into 3959 5 times, resulting in a remainder of 659.
Write down 5 as next digit of the result. 
Result so far: 19065.0
The remainder is 659 after subtracting 3300 from 3959.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6590, and continue the process.

Let's proceed to step 9:
If we divide 6590 by 660, we get 9 and a remainder of 650.
The next digit of our result is 9. 
Result so far: 19065.9
If we subtract 5940 from 6590, we get 650.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6500, and continue the process.

Advancing to step 10:
When dividing 6500 by 660, we get 9 with a remainder of 560.
The next digit of our result is 9. 
Result so far: 19065.99
The remainder is 560 after subtracting 5940 from 6500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5600, and continue the process.

Our division results in 19065.99 with a remaining 0.56.