842208 ÷ 21 
We want to figure out the number of times 842208 can be divided by 21.

Moving on to step 1:
The number 21 fits into 8 0 times, leaving a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Take the next digit (4) from the dividend and append it to 8, then repeat: 84 / 21

Moving on to step 2:
21 goes into 84 4 times with a remainder of 0.
The next digit of our result is 4. 
Result so far: 4.0
If we take 84 away from 84, we end up with 0.
Fetch the next digit (2) from the dividend, attach it to 0 and continue: 2 / 21

Advancing to step 3:
If we divide 2 by 21, we get 0 and a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 40.0
If we subtract 0 from 2, we get 2.
Append the next digit (2) from the dividend to 2 and continue with: 22 / 21

Step 4:
If we divide 22 by 21, we get 1 and a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 401.0
Deduct 21 from 22 and we're left with 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 21

On to step 5:
When dividing 10 by 21, we get 0 with a remainder of 10.
The next digit of our result is 0. 
Result so far: 4010.0
The remainder is 10 after subtracting 0 from 10.
Grab the next digit (8) from the dividend, add it to 10, then carry on: 108 / 21

Step 6:
21 can be fit into 108 5 times, resulting in a remainder of 3.
The number 5 becomes the next digit in our result. 
Result so far: 40105.0
Subtracting 105 from 108 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.

Advancing to step 7:
30 divided by 21 is 1 with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 40105.1
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.

Step 8:
If we divide 90 by 21, we get 4 and a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 40105.14
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.

Let's proceed to step 9:
The number 21 fits into 60 2 times, leaving a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 40105.142
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.

Step 10:
21 goes into 180 8 times with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 40105.1428
Deduct 168 from 180 and we're left 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:
If we divide 120 by 21, we get 5 and a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 40105.14285
If we subtract 105 from 120, we 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.

Moving on to step 12:
If we divide 150 by 21, we get 7 and a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 40105.142857
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 13:
When dividing 30 by 21, we get 1 with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 40105.1428571
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.

Moving on to step 14:
If we divide 90 by 21, we get 4 and a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 40105.14285714
Deduct 84 from 90 and we're left 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.

The final outcome is 40105.14285714, with a leftover of 6e-09.