990063 divided by 21 
We're looking to find how many times 21 goes into 990063.

Advancing to step 1:
The number 21 fits into 9 0 times, leaving a remainder of 9.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 9, we get 9.
Take the next digit (9) from the dividend and append it to 9, then repeat: 99 / 21

Advancing to step 2:
When dividing 99 by 21, we get 4 with a remainder of 15.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we subtract 84 from 99, we get 15.
Bring next digit (0) of the dividend behind the 15 and repeat the process: 150 / 21

Moving on to step 3:
When dividing 150 by 21, we get 7 with a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 47.0
Subtract 147 from 150 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 21

Moving on to step 4:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 471.0
Subtracting 21 from 30 leaves us with 9.
Bring next digit (6) of the dividend behind the 9 and repeat the process: 96 / 21

Going ahead to step 5:
96 divided by 21 is 4 with a remainder of 12.
Record the quotient 4 as the next digit in the result. 
Result so far: 4714.0
Deduct 84 from 96 and we're left with 12.
Include the next digit (3) from the dividend after 12, then repeat: 123 / 21

Going ahead to step 6:
123 divided by 21 is 5 with a remainder of 18.
Use 5 as the next digit of our solution. 
Result so far: 47145.0
The remainder is 18 after subtracting 105 from 123.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 7:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 47145.8
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 8:
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: 47145.85
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 9:
When dividing 150 by 21, we get 7 with a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 47145.857
Subtracting 147 from 150 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 10:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 47145.8571
The remainder is 9 after subtracting 21 from 30.
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 11:
90 divided by 21 is 4 with a remainder of 6.
The next digit of our result is 4. 
Result so far: 47145.85714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 12:
60 divided by 21 is 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 47145.857142
Subtracting 42 from 60 leaves us 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.

Advancing to step 13:
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: 47145.8571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 14:
When dividing 120 by 21, we get 5 with a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 47145.85714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

The final outcome is 47145.85714285, with a leftover of 1.5e-08.