We look at the division of 820388 by 21 
We're looking to find how many times 21 goes into 820388.

Step 1:
21 can be fit into 8 0 times, resulting in a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Bring next digit (2) of the dividend behind the 8 and repeat the process: 82 / 21

On to step 2:
21 goes into 82 3 times with a remainder of 19.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
If we take 63 away from 82, we end up with 19.
Bring next digit (0) of the dividend behind the 19 and repeat the process: 190 / 21

Moving on to step 3:
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: 39.0
If we subtract 189 from 190, we get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 21

On to step 4:
21 can be fit into 13 0 times, resulting in a remainder of 13.
Write down 0 as next digit of the result. 
Result so far: 390.0
The remainder is 13 after subtracting 0 from 13.
Bring next digit (8) of the dividend behind the 13 and repeat the process: 138 / 21

Going ahead to step 5:
If we divide 138 by 21, we get 6 and a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 3906.0
If we subtract 126 from 138, we get 12.
Bring next digit (8) of the dividend behind the 12 and repeat the process: 128 / 21

Advancing to step 6:
21 goes into 128 6 times with a remainder of 2.
Record the quotient 6 as the next digit in the result. 
Result so far: 39066.0
If we take 126 away from 128, we end up 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.

On to step 7:
When dividing 20 by 21, we get 0 with a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 39066.0
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 8:
When dividing 200 by 21, we get 9 with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 39066.09
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 9:
When dividing 110 by 21, we get 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 39066.095
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.

Advancing to step 10:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 39066.0952
Subtract 42 from 50 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 11:
21 can be fit into 80 3 times, resulting in a remainder of 17.
The next digit of our result is 3. 
Result so far: 39066.09523
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.

Moving on to step 12:
The number 21 fits into 170 8 times, leaving a remainder of 2.
The next digit of our result is 8. 
Result so far: 39066.095238
If we take 168 away from 170, we end up 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.

Let's proceed to step 13:
20 divided by 21 is 0 with a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 39066.095238
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 14:
21 goes into 200 9 times with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 39066.09523809
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

The quotient of the division is 39066.09523809, and the remainder is 1.1e-08.