Let's divide 399565 by 21
We want to divide 399565 by 21.

Moving on to step 1:
If we divide 3 by 21, we get 0 and a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 21

Let's proceed to step 2:
39 divided by 21 is 1 with a remainder of 18.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtract 21 from 39 to get 18.
Fetch the next digit (9) from the dividend, attach it to 18 and continue: 189 / 21

Let's proceed to step 3:
21 goes into 189 9 times with a remainder of 0.
Use 9 as the next digit of our solution. 
Result so far: 19.0
Deduct 189 from 189 and we're left with 0.
Bring next digit (5) of the dividend behind the 0 and repeat the process: 5 / 21

Moving on to step 4:
21 goes into 5 0 times with a remainder of 5.
The next digit of our result is 0. 
Result so far: 190.0
Deduct 0 from 5 and we're left with 5.
Take the next digit (6) from the dividend and append it to 5, then repeat: 56 / 21

Going ahead to step 5:
If we divide 56 by 21, we get 2 and a remainder of 14.
Use 2 as the next digit of our solution. 
Result so far: 1902.0
If we take 42 away from 56, we end up with 14.
Include the next digit (5) from the dividend after 14, then repeat: 145 / 21

Going ahead to step 6:
21 goes into 145 6 times with a remainder of 19.
Put 6 as the next digit of the answer. 
Result so far: 19026.0
If we take 126 away from 145, we end up 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.

Let's proceed to step 7:
When dividing 190 by 21, we get 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 19026.9
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.

On to step 8:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 19026.9
Deduct 0 from 10 and we're left 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.

Step 9:
100 divided by 21 is 4 with a remainder of 16.
The next digit of our result is 4. 
Result so far: 19026.904
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.

Moving on to step 10:
When dividing 160 by 21, we get 7 with a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 19026.9047
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.

Let's proceed 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: 19026.90476
Subtract 126 from 130 to 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.

On to step 12:
40 divided by 21 is 1 with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 19026.904761
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.

Going ahead to step 13:
190 divided by 21 is 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 19026.9047619
Subtracting 189 from 190 leaves us 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.

Moving on to step 14:
When dividing 10 by 21, we get 0 with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 19026.9047619
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.

After the division, we end up with 19026.9047619 and a remainder of 1e-08.