We look at the division of 620513 by 21 
Our goal is to divide 620513 by 21.

Advancing to step 1:
If we divide 6 by 21, we get 0 and a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Append the next digit (2) from the dividend to 6 and continue with: 62 / 21

Let's proceed to step 2:
When dividing 62 by 21, we get 2 with a remainder of 20.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
If we take 42 away from 62, we end up with 20.
Include the next digit (0) from the dividend after 20, then repeat: 200 / 21

Moving on to step 3:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 29.0
Deduct 189 from 200 and we're left with 11.
Take the next digit (5) from the dividend and append it to 11, then repeat: 115 / 21

Step 4:
21 goes into 115 5 times with a remainder of 10.
The next digit of our result is 5. 
Result so far: 295.0
If we subtract 105 from 115, we get 10.
Include the next digit (1) from the dividend after 10, then repeat: 101 / 21

On to step 5:
The number 21 fits into 101 4 times, leaving a remainder of 17.
Record the quotient 4 as the next digit in the result. 
Result so far: 2954.0
If we subtract 84 from 101, we get 17.
Append the next digit (3) from the dividend to 17 and continue with: 173 / 21

Going ahead to step 6:
21 goes into 173 8 times with a remainder of 5.
Use 8 as the next digit of our solution. 
Result so far: 29548.0
Subtracting 168 from 173 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 7:
If we divide 50 by 21, we get 2 and a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 29548.2
Deduct 42 from 50 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 8:
The number 21 fits into 80 3 times, leaving a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 29548.23
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 9:
170 divided by 21 is 8 with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 29548.238
Deduct 168 from 170 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 10:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 29548.238
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 11:
21 can be fit into 200 9 times, resulting in a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 29548.23809
Subtracting 189 from 200 leaves us with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Moving on to step 12:
21 goes into 110 5 times with a remainder of 5.
The next digit of our result is 5. 
Result so far: 29548.238095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 13:
21 goes into 50 2 times with a remainder of 8.
The next digit of our result is 2. 
Result so far: 29548.2380952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 14:
80 divided by 21 is 3 with a remainder of 17.
The next digit of our result is 3. 
Result so far: 29548.23809523
Subtracting 63 from 80 leaves us with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Our division results in 29548.23809523 with a remaining 1.7e-08.