646849 divided by 21 
Our goal is to divide 646849 by 21.

Step 1:
21 can be fit into 6 0 times, resulting in a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 21

Step 2:
21 can be fit into 64 3 times, resulting in a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
If we subtract 63 from 64, we get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 21

Going ahead to step 3:
The number 21 fits into 16 0 times, leaving a remainder of 16.
Use 0 as the next digit of our solution. 
Result so far: 30.0
The remainder is 16 after subtracting 0 from 16.
Take the next digit (8) from the dividend and append it to 16, then repeat: 168 / 21

On to step 4:
21 goes into 168 8 times with a remainder of 0.
The number 8 becomes the next digit in our result. 
Result so far: 308.0
If we take 168 away from 168, we end up with 0.
Include the next digit (4) from the dividend after 0, then repeat: 4 / 21

Going ahead to step 5:
4 divided by 21 is 0 with a remainder of 4.
The next digit of our result is 0. 
Result so far: 3080.0
The remainder is 4 after subtracting 0 from 4.
Take the next digit (9) from the dividend and append it to 4, then repeat: 49 / 21

Going ahead to step 6:
21 goes into 49 2 times with a remainder of 7.
The number 2 becomes the next digit in our result. 
Result so far: 30802.0
If we take 42 away from 49, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 7:
21 can be fit into 70 3 times, resulting in a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 30802.3
If we take 63 away from 70, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

On to step 8:
21 goes into 70 3 times with a remainder of 7.
Record the quotient 3 as the next digit in the result. 
Result so far: 30802.33
Subtracting 63 from 70 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

The quotient of the division is 30802.33, and the remainder is 0.007.