We look at the division of 21728788 by 509 
We want to divide 21728788 by 509.

Moving on to step 1:
2 divided by 509 is 0 with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 509

Let's proceed to step 2:
509 can be fit into 21 0 times, resulting in a remainder of 21.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 21 and we're left with 21.
Fetch the next digit (7) from the dividend, attach it to 21 and continue: 217 / 509

On to step 3:
509 can be fit into 217 0 times, resulting in a remainder of 217.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 217 after subtracting 0 from 217.
Take the next digit (2) from the dividend and append it to 217, then repeat: 2172 / 509

On to step 4:
The number 509 fits into 2172 4 times, leaving a remainder of 136.
The next digit of our result is 4. 
Result so far: 4.0
If we take 2036 away from 2172, we end up with 136.
Include the next digit (8) from the dividend after 136, then repeat: 1368 / 509

Going ahead to step 5:
When dividing 1368 by 509, we get 2 with a remainder of 350.
Write down 2 as next digit of the result. 
Result so far: 42.0
Subtracting 1018 from 1368 leaves us with 350.
Bring next digit (7) of the dividend behind the 350 and repeat the process: 3507 / 509

Moving on to step 6:
If we divide 3507 by 509, we get 6 and a remainder of 453.
Put 6 as the next digit of the answer. 
Result so far: 426.0
If we take 3054 away from 3507, we end up with 453.
Include the next digit (8) from the dividend after 453, then repeat: 4538 / 509

Step 7:
When dividing 4538 by 509, we get 8 with a remainder of 466.
Use 8 as the next digit of our solution. 
Result so far: 4268.0
Deduct 4072 from 4538 and we're left with 466.
Bring next digit (8) of the dividend behind the 466 and repeat the process: 4668 / 509

Let's proceed to step 8:
If we divide 4668 by 509, we get 9 and a remainder of 87.
Record the quotient 9 as the next digit in the result. 
Result so far: 42689.0
If we subtract 4581 from 4668, we get 87.
Since there are no more digits in the dividend, we add a zero to the remainder making it 870, and continue the process.

Advancing to step 9:
When dividing 870 by 509, we get 1 with a remainder of 361.
Put 1 as the next digit of the answer. 
Result so far: 42689.1
The remainder is 361 after subtracting 509 from 870.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3610, and continue the process.

Going ahead to step 10:
509 can be fit into 3610 7 times, resulting in a remainder of 47.
Put 7 as the next digit of the answer. 
Result so far: 42689.17
Deduct 3563 from 3610 and we're left with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Advancing to step 11:
The number 509 fits into 470 0 times, leaving a remainder of 470.
The next digit of our result is 0. 
Result so far: 42689.17
Subtract 0 from 470 to get 470.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4700, and continue the process.

Going ahead to step 12:
509 goes into 4700 9 times with a remainder of 119.
The number 9 becomes the next digit in our result. 
Result so far: 42689.1709
The remainder is 119 after subtracting 4581 from 4700.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1190, and continue the process.

On to step 13:
509 goes into 1190 2 times with a remainder of 172.
Use 2 as the next digit of our solution. 
Result so far: 42689.17092
Subtracting 1018 from 1190 leaves us with 172.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1720, and continue the process.

Let's proceed to step 14:
The number 509 fits into 1720 3 times, leaving a remainder of 193.
Write down 3 as next digit of the result. 
Result so far: 42689.170923
Subtracting 1527 from 1720 leaves us with 193.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1930, and continue the process.

Let's proceed to step 15:
If we divide 1930 by 509, we get 3 and a remainder of 403.
Put 3 as the next digit of the answer. 
Result so far: 42689.1709233
If we take 1527 away from 1930, we end up with 403.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4030, and continue the process.

After the division, we end up with 42689.1709233 and a remainder of 4.03e-06.