We're dividing 457339 by 21 
We want to divide 457339 by 21.

On to step 1:
The number 21 fits into 4 0 times, leaving a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Grab the next digit (5) from the dividend, add it to 4, then carry on: 45 / 21

Going ahead to step 2:
45 divided by 21 is 2 with a remainder of 3.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtract 42 from 45 to get 3.
Include the next digit (7) from the dividend after 3, then repeat: 37 / 21

Moving on to step 3:
If we divide 37 by 21, we get 1 and a remainder of 16.
The number 1 becomes the next digit in our result. 
Result so far: 21.0
If we take 21 away from 37, we end up with 16.
Fetch the next digit (3) from the dividend, attach it to 16 and continue: 163 / 21

Going ahead to step 4:
When dividing 163 by 21, we get 7 with a remainder of 16.
Put 7 as the next digit of the answer. 
Result so far: 217.0
Deduct 147 from 163 and we're left with 16.
Append the next digit (3) from the dividend to 16 and continue with: 163 / 21

Moving on to step 5:
21 goes into 163 7 times with a remainder of 16.
The number 7 becomes the next digit in our result. 
Result so far: 2177.0
The remainder is 16 after subtracting 147 from 163.
Take the next digit (9) from the dividend and append it to 16, then repeat: 169 / 21

Moving on to step 6:
The number 21 fits into 169 8 times, leaving a remainder of 1.
Write down 8 as next digit of the result. 
Result so far: 21778.0
If we take 168 away from 169, 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 7:
10 divided by 21 is 0 with a remainder of 10.
The next digit of our result is 0. 
Result so far: 21778.0
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.

Step 8:
21 goes into 100 4 times with a remainder of 16.
The next digit of our result is 4. 
Result so far: 21778.04
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 9:
21 can be fit into 160 7 times, resulting in a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 21778.047
If we take 147 away from 160, we end up 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.

Moving on to step 10:
The number 21 fits into 130 6 times, leaving a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 21778.0476
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.

Moving on to step 11:
21 goes into 40 1 times with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 21778.04761
Subtract 21 from 40 to 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.

On to step 12:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 21778.047619
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.

Going ahead to step 13:
21 goes into 10 0 times with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 21778.047619
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 14:
When dividing 100 by 21, we get 4 with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 21778.04761904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The final outcome is 21778.04761904, with a leftover of 1.6e-08.