Let's divide 390313 by 21
Let's see how many times 21 fits into 390313.

Let's proceed to step 1:
21 can be fit into 3 0 times, resulting in a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 21

Let's proceed to step 2:
The number 21 fits into 39 1 times, leaving a remainder of 18.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 21 away from 39, we end up with 18.
Bring next digit (0) of the dividend behind the 18 and repeat the process: 180 / 21

On to step 3:
21 goes into 180 8 times with a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 18.0
Deduct 168 from 180 and we're left with 12.
Bring next digit (3) of the dividend behind the 12 and repeat the process: 123 / 21

Advancing to step 4:
21 goes into 123 5 times with a remainder of 18.
Write down 5 as next digit of the result. 
Result so far: 185.0
Subtracting 105 from 123 leaves us with 18.
Include the next digit (1) from the dividend after 18, then repeat: 181 / 21

Let's proceed to step 5:
21 goes into 181 8 times with a remainder of 13.
Write down 8 as next digit of the result. 
Result so far: 1858.0
If we subtract 168 from 181, we get 13.
Grab the next digit (3) from the dividend, add it to 13, then carry on: 133 / 21

Step 6:
133 divided by 21 is 6 with a remainder of 7.
Use 6 as the next digit of our solution. 
Result so far: 18586.0
If we subtract 126 from 133, we get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 7:
70 divided by 21 is 3 with a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 18586.3
If we take 63 away from 70, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

On to step 8:
If we divide 70 by 21, we get 3 and a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 18586.33
If we subtract 63 from 70, we get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

In conclusion, the division gives 18586.33 with a balance of 0.007.