We're dividing 99905082 by 21 
We want to figure out the number of times 99905082 can be divided by 21.

Moving on to step 1:
If we divide 9 by 21, we get 0 and 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.
Grab the next digit (9) from the dividend, add it to 9, then carry on: 99 / 21

Step 2:
99 divided by 21 is 4 with a remainder of 15.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
Subtracting 84 from 99 leaves us with 15.
Grab the next digit (9) from the dividend, add it to 15, then carry on: 159 / 21

Advancing to step 3:
21 goes into 159 7 times with a remainder of 12.
The number 7 becomes the next digit in our result. 
Result so far: 47.0
Deduct 147 from 159 and we're left with 12.
Grab the next digit (0) from the dividend, add it to 12, then carry on: 120 / 21

Let's proceed to step 4:
21 goes into 120 5 times with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 475.0
Subtract 105 from 120 to get 15.
Take the next digit (5) from the dividend and append it to 15, then repeat: 155 / 21

Let's proceed to step 5:
When dividing 155 by 21, we get 7 with a remainder of 8.
Record the quotient 7 as the next digit in the result. 
Result so far: 4757.0
Subtracting 147 from 155 leaves us with 8.
Append the next digit (0) from the dividend to 8 and continue with: 80 / 21

Moving on to step 6:
80 divided by 21 is 3 with a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 47573.0
If we take 63 away from 80, we end up with 17.
Bring next digit (8) of the dividend behind the 17 and repeat the process: 178 / 21

Step 7:
The number 21 fits into 178 8 times, leaving a remainder of 10.
Write down 8 as next digit of the result. 
Result so far: 475738.0
If we subtract 168 from 178, we get 10.
Append the next digit (2) from the dividend to 10 and continue with: 102 / 21

On to step 8:
21 goes into 102 4 times with a remainder of 18.
Use 4 as the next digit of our solution. 
Result so far: 4757384.0
Subtract 84 from 102 to 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.

Step 9:
180 divided by 21 is 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 4757384.8
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.

Advancing to step 10:
21 goes into 120 5 times with a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 4757384.85
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.

Moving on to step 11:
21 goes into 150 7 times with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 4757384.857
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.

Advancing to step 12:
30 divided by 21 is 1 with a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 4757384.8571
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 13:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 4757384.85714
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.

On to step 14:
21 can be fit into 60 2 times, resulting in a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 4757384.857142
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.

Going ahead to step 15:
The number 21 fits into 180 8 times, leaving a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 4757384.8571428
If we subtract 168 from 180, we 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.

Moving on to step 16:
21 goes into 120 5 times with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 4757384.85714285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

In conclusion, the division gives 4757384.85714285 with a balance of 1.5e-08.