We divide 990510 by 21
We want to figure out the number of times 990510 can be divided by 21.

Going ahead to step 1:
If we divide 9 by 21, we get 0 and a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Take the next digit (9) from the dividend and append it to 9, then repeat: 99 / 21

Moving on to step 2:
99 divided by 21 is 4 with a remainder of 15.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we take 84 away from 99, we end up with 15.
Bring next digit (0) of the dividend behind the 15 and repeat the process: 150 / 21

Advancing to step 3:
150 divided by 21 is 7 with a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 47.0
Deduct 147 from 150 and we're left with 3.
Bring next digit (5) of the dividend behind the 3 and repeat the process: 35 / 21

Advancing to step 4:
21 goes into 35 1 times with a remainder of 14.
Record the quotient 1 as the next digit in the result. 
Result so far: 471.0
Deduct 21 from 35 and we're left with 14.
Take the next digit (1) from the dividend and append it to 14, then repeat: 141 / 21

Step 5:
When dividing 141 by 21, we get 6 with a remainder of 15.
The next digit of our result is 6. 
Result so far: 4716.0
If we subtract 126 from 141, we get 15.
Grab the next digit (0) from the dividend, add it to 15, then carry on: 150 / 21

On to step 6:
21 can be fit into 150 7 times, resulting in a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 47167.0
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.

Step 7:
When dividing 30 by 21, we get 1 with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 47167.1
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.

On to step 8:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 47167.14
Subtracting 84 from 90 leaves us 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 9:
21 goes into 60 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 47167.142
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.

On to step 10:
When dividing 180 by 21, we get 8 with a remainder of 12.
The next digit of our result is 8. 
Result so far: 47167.1428
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.

Going ahead to step 11:
21 goes into 120 5 times with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 47167.14285
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.

Advancing to step 12:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 47167.142857
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 13:
21 goes into 30 1 times with a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 47167.1428571
If we take 21 away from 30, we end up 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.

Step 14:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 47167.14285714
If we subtract 84 from 90, we 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.

In conclusion, the division gives 47167.14285714 with a balance of 6e-09.