Let's divide 310639 by 21
Let's see how many times 21 fits into 310639.

Step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Take the next digit (1) from the dividend and append it to 3, then repeat: 31 / 21

Step 2:
21 goes into 31 1 times with a remainder of 10.
Put 1 as the next digit of the answer. 
Result so far: 1.0
The remainder is 10 after subtracting 21 from 31.
Take the next digit (0) from the dividend and append it to 10, then repeat: 100 / 21

Step 3:
21 goes into 100 4 times with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 14.0
Subtract 84 from 100 to get 16.
Fetch the next digit (6) from the dividend, attach it to 16 and continue: 166 / 21

Step 4:
The number 21 fits into 166 7 times, leaving a remainder of 19.
Put 7 as the next digit of the answer. 
Result so far: 147.0
If we subtract 147 from 166, we get 19.
Grab the next digit (3) from the dividend, add it to 19, then carry on: 193 / 21

Step 5:
21 can be fit into 193 9 times, resulting in a remainder of 4.
The next digit of our result is 9. 
Result so far: 1479.0
If we subtract 189 from 193, we get 4.
Grab the next digit (9) from the dividend, add it to 4, then carry on: 49 / 21

Going ahead to step 6:
49 divided by 21 is 2 with a remainder of 7.
Use 2 as the next digit of our solution. 
Result so far: 14792.0
Subtracting 42 from 49 leaves us 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.

Let's proceed to step 7:
21 goes into 70 3 times with a remainder of 7.
The next digit of our result is 3. 
Result so far: 14792.3
Deduct 63 from 70 and we're left 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.

Going ahead to step 8:
The number 21 fits into 70 3 times, leaving a remainder of 7.
Use 3 as the next digit of our solution. 
Result so far: 14792.33
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 14792.33 with a balance of 0.007.