Let's divide 638905 by 21
We're looking to find how many times 21 goes into 638905.

Moving on to step 1:
6 divided by 21 is 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 21

Moving on to step 2:
The number 21 fits into 63 3 times, leaving a remainder of 0.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 0 after subtracting 63 from 63.
Fetch the next digit (8) from the dividend, attach it to 0 and continue: 8 / 21

Moving on to step 3:
The number 21 fits into 8 0 times, leaving a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 30.0
The remainder is 8 after subtracting 0 from 8.
Include the next digit (9) from the dividend after 8, then repeat: 89 / 21

Moving on to step 4:
If we divide 89 by 21, we get 4 and a remainder of 5.
The number 4 becomes the next digit in our result. 
Result so far: 304.0
Subtracting 84 from 89 leaves us with 5.
Take the next digit (0) from the dividend and append it to 5, then repeat: 50 / 21

Going ahead to step 5:
When dividing 50 by 21, we get 2 with a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 3042.0
Deduct 42 from 50 and we're left with 8.
Bring next digit (5) of the dividend behind the 8 and repeat the process: 85 / 21

Step 6:
When dividing 85 by 21, we get 4 with a remainder of 1.
Write down 4 as next digit of the result. 
Result so far: 30424.0
If we subtract 84 from 85, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 7:
21 can be fit into 10 0 times, resulting in a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 30424.0
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 8:
100 divided by 21 is 4 with a remainder of 16.
The next digit of our result is 4. 
Result so far: 30424.04
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 9:
If we divide 160 by 21, we get 7 and a remainder of 13.
The next digit of our result is 7. 
Result so far: 30424.047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 10:
130 divided by 21 is 6 with a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 30424.0476
If we take 126 away from 130, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 11:
21 goes into 40 1 times with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 30424.04761
If we take 21 away from 40, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 12:
21 goes into 190 9 times with a remainder of 1.
The next digit of our result is 9. 
Result so far: 30424.047619
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 13:
If we divide 10 by 21, we get 0 and a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 30424.047619
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 14:
The number 21 fits into 100 4 times, leaving a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 30424.04761904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The quotient of the division is 30424.04761904, and the remainder is 1.6e-08.