We're dividing 513742 by 21 
We want to divide 513742 by 21.

Going ahead to step 1:
21 can be fit into 5 0 times, resulting in a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 21

Going ahead to step 2:
21 can be fit into 51 2 times, resulting in a remainder of 9.
Put 2 as the next digit of the answer. 
Result so far: 2.0
The remainder is 9 after subtracting 42 from 51.
Include the next digit (3) from the dividend after 9, then repeat: 93 / 21

Moving on to step 3:
21 goes into 93 4 times with a remainder of 9.
The number 4 becomes the next digit in our result. 
Result so far: 24.0
Subtract 84 from 93 to get 9.
Include the next digit (7) from the dividend after 9, then repeat: 97 / 21

On to step 4:
The number 21 fits into 97 4 times, leaving a remainder of 13.
The number 4 becomes the next digit in our result. 
Result so far: 244.0
The remainder is 13 after subtracting 84 from 97.
Grab the next digit (4) from the dividend, add it to 13, then carry on: 134 / 21

Advancing to step 5:
When dividing 134 by 21, we get 6 with a remainder of 8.
Use 6 as the next digit of our solution. 
Result so far: 2446.0
If we take 126 away from 134, we end up with 8.
Append the next digit (2) from the dividend to 8 and continue with: 82 / 21

On to step 6:
82 divided by 21 is 3 with a remainder of 19.
Put 3 as the next digit of the answer. 
Result so far: 24463.0
If we subtract 63 from 82, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 7:
If we divide 190 by 21, we get 9 and a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 24463.9
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 8:
21 goes into 10 0 times with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 24463.9
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 9:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 24463.904
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Advancing to step 10:
The number 21 fits into 160 7 times, leaving a remainder of 13.
The next digit of our result is 7. 
Result so far: 24463.9047
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 11:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 24463.90476
Deduct 126 from 130 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 12:
21 can be fit into 40 1 times, resulting in a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 24463.904761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 13:
If we divide 190 by 21, we get 9 and a remainder of 1.
The next digit of our result is 9. 
Result so far: 24463.9047619
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 14:
21 goes into 10 0 times with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 24463.9047619
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

After the division, we end up with 24463.9047619 and a remainder of 1e-08.