We divide 642236 by 21
Our goal is to divide 642236 by 21.

Step 1:
The number 21 fits into 6 0 times, leaving a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 21

Step 2:
21 can be fit into 64 3 times, resulting in a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Deduct 63 from 64 and we're left with 1.
Fetch the next digit (2) from the dividend, attach it to 1 and continue: 12 / 21

On to step 3:
When dividing 12 by 21, we get 0 with a remainder of 12.
Put 0 as the next digit of the answer. 
Result so far: 30.0
The remainder is 12 after subtracting 0 from 12.
Fetch the next digit (2) from the dividend, attach it to 12 and continue: 122 / 21

Let's proceed to step 4:
The number 21 fits into 122 5 times, leaving a remainder of 17.
Put 5 as the next digit of the answer. 
Result so far: 305.0
Subtracting 105 from 122 leaves us with 17.
Take the next digit (3) from the dividend and append it to 17, then repeat: 173 / 21

Step 5:
If we divide 173 by 21, we get 8 and a remainder of 5.
The next digit of our result is 8. 
Result so far: 3058.0
If we subtract 168 from 173, we get 5.
Grab the next digit (6) from the dividend, add it to 5, then carry on: 56 / 21

On to step 6:
When dividing 56 by 21, we get 2 with a remainder of 14.
The number 2 becomes the next digit in our result. 
Result so far: 30582.0
If we subtract 42 from 56, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Step 7:
The number 21 fits into 140 6 times, leaving a remainder of 14.
The number 6 becomes the next digit in our result. 
Result so far: 30582.6
Deduct 126 from 140 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 8:
If we divide 140 by 21, we get 6 and a remainder of 14.
The number 6 becomes the next digit in our result. 
Result so far: 30582.66
Subtract 126 from 140 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

After the division, we end up with 30582.66 and a remainder of 0.014.