We're dividing 20403187 by 813 
Let's see how many times 813 fits into 20403187.

Going ahead to step 1:
When dividing 2 by 813, we get 0 with a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 813

On to step 2:
813 goes into 20 0 times with a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 20 after subtracting 0 from 20.
Include the next digit (4) from the dividend after 20, then repeat: 204 / 813

Moving on to step 3:
813 goes into 204 0 times with a remainder of 204.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 204, we get 204.
Take the next digit (0) from the dividend and append it to 204, then repeat: 2040 / 813

Moving on to step 4:
When dividing 2040 by 813, we get 2 with a remainder of 414.
Put 2 as the next digit of the answer. 
Result so far: 2.0
If we take 1626 away from 2040, we end up with 414.
Append the next digit (3) from the dividend to 414 and continue with: 4143 / 813

Going ahead to step 5:
The number 813 fits into 4143 5 times, leaving a remainder of 78.
The number 5 becomes the next digit in our result. 
Result so far: 25.0
If we take 4065 away from 4143, we end up with 78.
Grab the next digit (1) from the dividend, add it to 78, then carry on: 781 / 813

Advancing to step 6:
The number 813 fits into 781 0 times, leaving a remainder of 781.
Put 0 as the next digit of the answer. 
Result so far: 250.0
Deduct 0 from 781 and we're left with 781.
Append the next digit (8) from the dividend to 781 and continue with: 7818 / 813

Advancing to step 7:
The number 813 fits into 7818 9 times, leaving a remainder of 501.
Put 9 as the next digit of the answer. 
Result so far: 2509.0
If we take 7317 away from 7818, we end up with 501.
Bring next digit (7) of the dividend behind the 501 and repeat the process: 5017 / 813

Going ahead to step 8:
The number 813 fits into 5017 6 times, leaving a remainder of 139.
Put 6 as the next digit of the answer. 
Result so far: 25096.0
If we take 4878 away from 5017, we end up with 139.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1390, and continue the process.

On to step 9:
813 goes into 1390 1 times with a remainder of 577.
The number 1 becomes the next digit in our result. 
Result so far: 25096.1
Subtract 813 from 1390 to get 577.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5770, and continue the process.

Let's proceed to step 10:
813 can be fit into 5770 7 times, resulting in a remainder of 79.
The number 7 becomes the next digit in our result. 
Result so far: 25096.17
Subtract 5691 from 5770 to get 79.
Since there are no more digits in the dividend, we add a zero to the remainder making it 790, and continue the process.

Advancing to step 11:
When dividing 790 by 813, we get 0 with a remainder of 790.
Put 0 as the next digit of the answer. 
Result so far: 25096.17
Deduct 0 from 790 and we're left with 790.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7900, and continue the process.

Going ahead to step 12:
If we divide 7900 by 813, we get 9 and a remainder of 583.
Write down 9 as next digit of the result. 
Result so far: 25096.1709
Subtracting 7317 from 7900 leaves us with 583.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5830, and continue the process.

Advancing to step 13:
The number 813 fits into 5830 7 times, leaving a remainder of 139.
Put 7 as the next digit of the answer. 
Result so far: 25096.17097
If we subtract 5691 from 5830, we get 139.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1390, and continue the process.

Advancing to step 14:
The number 813 fits into 1390 1 times, leaving a remainder of 577.
Write down 1 as next digit of the result. 
Result so far: 25096.170971
Deduct 813 from 1390 and we're left with 577.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5770, and continue the process.

Let's proceed to step 15:
If we divide 5770 by 813, we get 7 and a remainder of 79.
Write down 7 as next digit of the result. 
Result so far: 25096.1709717
If we subtract 5691 from 5770, we get 79.
Since there are no more digits in the dividend, we add a zero to the remainder making it 790, and continue the process.

Advancing to step 16:
813 goes into 790 0 times with a remainder of 790.
Write down 0 as next digit of the result. 
Result so far: 25096.1709717
If we take 0 away from 790, we end up with 790.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7900, and continue the process.

The final outcome is 25096.1709717, with a leftover of 7.9e-07.