12902459 divided by 866 
We want to divide 12902459 by 866.

Let's proceed to step 1:
1 divided by 866 is 0 with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 866

Going ahead to step 2:
When dividing 12 by 866, we get 0 with a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 12 leaves us with 12.
Fetch the next digit (9) from the dividend, attach it to 12 and continue: 129 / 866

Let's proceed to step 3:
129 divided by 866 is 0 with a remainder of 129.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 129 to get 129.
Grab the next digit (0) from the dividend, add it to 129, then carry on: 1290 / 866

Going ahead to step 4:
If we divide 1290 by 866, we get 1 and a remainder of 424.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 866 from 1290 leaves us with 424.
Fetch the next digit (2) from the dividend, attach it to 424 and continue: 4242 / 866

Advancing to step 5:
866 can be fit into 4242 4 times, resulting in a remainder of 778.
The number 4 becomes the next digit in our result. 
Result so far: 14.0
Subtract 3464 from 4242 to get 778.
Take the next digit (4) from the dividend and append it to 778, then repeat: 7784 / 866

On to step 6:
If we divide 7784 by 866, we get 8 and a remainder of 856.
The number 8 becomes the next digit in our result. 
Result so far: 148.0
Subtract 6928 from 7784 to get 856.
Append the next digit (5) from the dividend to 856 and continue with: 8565 / 866

Advancing to step 7:
If we divide 8565 by 866, we get 9 and a remainder of 771.
Use 9 as the next digit of our solution. 
Result so far: 1489.0
The remainder is 771 after subtracting 7794 from 8565.
Take the next digit (9) from the dividend and append it to 771, then repeat: 7719 / 866

Let's proceed to step 8:
7719 divided by 866 is 8 with a remainder of 791.
Put 8 as the next digit of the answer. 
Result so far: 14898.0
Deduct 6928 from 7719 and we're left with 791.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7910, and continue the process.

On to step 9:
When dividing 7910 by 866, we get 9 with a remainder of 116.
The next digit of our result is 9. 
Result so far: 14898.9
If we subtract 7794 from 7910, we get 116.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1160, and continue the process.

Let's proceed to step 10:
The number 866 fits into 1160 1 times, leaving a remainder of 294.
The next digit of our result is 1. 
Result so far: 14898.91
Deduct 866 from 1160 and we're left with 294.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2940, and continue the process.

Going ahead to step 11:
866 goes into 2940 3 times with a remainder of 342.
The next digit of our result is 3. 
Result so far: 14898.913
The remainder is 342 after subtracting 2598 from 2940.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3420, and continue the process.

Going ahead to step 12:
If we divide 3420 by 866, we get 3 and a remainder of 822.
Use 3 as the next digit of our solution. 
Result so far: 14898.9133
If we subtract 2598 from 3420, we get 822.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8220, and continue the process.

The final outcome is 14898.9133, with a leftover of 0.00822.