663039 ÷ 21 
We want to divide 663039 by 21.

Advancing to step 1:
When dividing 6 by 21, we get 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 21

Step 2:
21 goes into 66 3 times with a remainder of 3.
The next digit of our result is 3. 
Result so far: 3.0
If we subtract 63 from 66, we get 3.
Grab the next digit (3) from the dividend, add it to 3, then carry on: 33 / 21

Going ahead to step 3:
If we divide 33 by 21, we get 1 and a remainder of 12.
Record the quotient 1 as the next digit in the result. 
Result so far: 31.0
Subtract 21 from 33 to get 12.
Append the next digit (0) from the dividend to 12 and continue with: 120 / 21

On to step 4:
The number 21 fits into 120 5 times, leaving a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 315.0
The remainder is 15 after subtracting 105 from 120.
Append the next digit (3) from the dividend to 15 and continue with: 153 / 21

Advancing to step 5:
If we divide 153 by 21, we get 7 and a remainder of 6.
Put 7 as the next digit of the answer. 
Result so far: 3157.0
If we take 147 away from 153, we end up with 6.
Take the next digit (9) from the dividend and append it to 6, then repeat: 69 / 21

Going ahead to step 6:
21 goes into 69 3 times with a remainder of 6.
Write down 3 as next digit of the result. 
Result so far: 31573.0
If we take 63 away from 69, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 7:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 31573.2
Deduct 42 from 60 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 8:
180 divided by 21 is 8 with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 31573.28
If we take 168 away from 180, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 9:
21 goes into 120 5 times with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 31573.285
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 10:
When dividing 150 by 21, we get 7 with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 31573.2857
Subtract 147 from 150 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 11:
If we divide 30 by 21, we get 1 and a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 31573.28571
Subtracting 21 from 30 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 12:
90 divided by 21 is 4 with a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 31573.285714
If we take 84 away from 90, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 13:
60 divided by 21 is 2 with a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 31573.2857142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 14:
21 goes into 180 8 times with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 31573.28571428
Subtracting 168 from 180 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

In conclusion, the division gives 31573.28571428 with a balance of 1.2e-08.