12403559 ÷ 975 
Our goal is to divide 12403559 by 975.

Step 1:
When dividing 1 by 975, we get 0 with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Fetch the next digit (2) from the dividend, attach it to 1 and continue: 12 / 975

Step 2:
12 divided by 975 is 0 with a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 12 leaves us with 12.
Fetch the next digit (4) from the dividend, attach it to 12 and continue: 124 / 975

Step 3:
975 can be fit into 124 0 times, resulting in a remainder of 124.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 124 leaves us with 124.
Append the next digit (0) from the dividend to 124 and continue with: 1240 / 975

Let's proceed to step 4:
975 can be fit into 1240 1 times, resulting in a remainder of 265.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
The remainder is 265 after subtracting 975 from 1240.
Append the next digit (3) from the dividend to 265 and continue with: 2653 / 975

Moving on to step 5:
The number 975 fits into 2653 2 times, leaving a remainder of 703.
Put 2 as the next digit of the answer. 
Result so far: 12.0
Subtracting 1950 from 2653 leaves us with 703.
Include the next digit (5) from the dividend after 703, then repeat: 7035 / 975

On to step 6:
If we divide 7035 by 975, we get 7 and a remainder of 210.
The next digit of our result is 7. 
Result so far: 127.0
Subtract 6825 from 7035 to get 210.
Grab the next digit (5) from the dividend, add it to 210, then carry on: 2105 / 975

Going ahead to step 7:
If we divide 2105 by 975, we get 2 and a remainder of 155.
Put 2 as the next digit of the answer. 
Result so far: 1272.0
Deduct 1950 from 2105 and we're left with 155.
Take the next digit (9) from the dividend and append it to 155, then repeat: 1559 / 975

Moving on to step 8:
When dividing 1559 by 975, we get 1 with a remainder of 584.
Record the quotient 1 as the next digit in the result. 
Result so far: 12721.0
Subtracting 975 from 1559 leaves us with 584.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5840, and continue the process.

Let's proceed to step 9:
If we divide 5840 by 975, we get 5 and a remainder of 965.
Use 5 as the next digit of our solution. 
Result so far: 12721.5
If we take 4875 away from 5840, we end up with 965.
Since there are no more digits in the dividend, we add a zero to the remainder making it 9650, and continue the process.

Advancing to step 10:
If we divide 9650 by 975, we get 9 and a remainder of 875.
The next digit of our result is 9. 
Result so far: 12721.59
If we subtract 8775 from 9650, we get 875.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8750, and continue the process.

Moving on to step 11:
The number 975 fits into 8750 8 times, leaving a remainder of 950.
The number 8 becomes the next digit in our result. 
Result so far: 12721.598
Subtract 7800 from 8750 to get 950.
Since there are no more digits in the dividend, we add a zero to the remainder making it 9500, and continue the process.

Let's proceed to step 12:
975 can be fit into 9500 9 times, resulting in a remainder of 725.
The next digit of our result is 9. 
Result so far: 12721.5989
The remainder is 725 after subtracting 8775 from 9500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7250, and continue the process.

Moving on to step 13:
975 can be fit into 7250 7 times, resulting in a remainder of 425.
The number 7 becomes the next digit in our result. 
Result so far: 12721.59897
If we take 6825 away from 7250, we end up with 425.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4250, and continue the process.

On to step 14:
4250 divided by 975 is 4 with a remainder of 350.
Write down 4 as next digit of the result. 
Result so far: 12721.598974
Subtracting 3900 from 4250 leaves us with 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

Let's proceed to step 15:
When dividing 3500 by 975, we get 3 with a remainder of 575.
Put 3 as the next digit of the answer. 
Result so far: 12721.5989743
Subtract 2925 from 3500 to get 575.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5750, and continue the process.

Let's proceed to step 16:
975 goes into 5750 5 times with a remainder of 875.
The number 5 becomes the next digit in our result. 
Result so far: 12721.59897435
Subtracting 4875 from 5750 leaves us with 875.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8750, and continue the process.

The final outcome is 12721.59897435, with a leftover of 8.75e-07.