620899 divided by 21 
Our goal is to divide 620899 by 21.

Step 1:
If we divide 6 by 21, we get 0 and a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Include the next digit (2) from the dividend after 6, then repeat: 62 / 21

Step 2:
If we divide 62 by 21, we get 2 and a remainder of 20.
The next digit of our result is 2. 
Result so far: 2.0
The remainder is 20 after subtracting 42 from 62.
Bring next digit (0) of the dividend behind the 20 and repeat the process: 200 / 21

Moving on to step 3:
If we divide 200 by 21, we get 9 and a remainder of 11.
The next digit of our result is 9. 
Result so far: 29.0
If we subtract 189 from 200, we get 11.
Grab the next digit (8) from the dividend, add it to 11, then carry on: 118 / 21

On to step 4:
If we divide 118 by 21, we get 5 and a remainder of 13.
Put 5 as the next digit of the answer. 
Result so far: 295.0
If we take 105 away from 118, we end up with 13.
Take the next digit (9) from the dividend and append it to 13, then repeat: 139 / 21

Advancing to step 5:
21 goes into 139 6 times with a remainder of 13.
The number 6 becomes the next digit in our result. 
Result so far: 2956.0
If we subtract 126 from 139, we get 13.
Fetch the next digit (9) from the dividend, attach it to 13 and continue: 139 / 21

Let's proceed to step 6:
139 divided by 21 is 6 with a remainder of 13.
The next digit of our result is 6. 
Result so far: 29566.0
If we take 126 away from 139, 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 7:
21 can be fit into 130 6 times, resulting in a remainder of 4.
The next digit of our result is 6. 
Result so far: 29566.6
If we subtract 126 from 130, we get 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 8:
21 goes into 40 1 times with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 29566.61
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 9:
21 goes into 190 9 times with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 29566.619
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 10:
21 goes into 10 0 times with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 29566.619
Subtracting 0 from 10 leaves us with 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 11:
21 goes into 100 4 times with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 29566.61904
The remainder is 16 after subtracting 84 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 12:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 29566.619047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 13:
The number 21 fits into 130 6 times, leaving a remainder of 4.
The next digit of our result is 6. 
Result so far: 29566.6190476
Subtracting 126 from 130 leaves us 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.

Going ahead to step 14:
When dividing 40 by 21, we get 1 with a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 29566.61904761
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

The final outcome is 29566.61904761, with a leftover of 1.9e-08.