We look at the division of 863093 by 21 
We want to divide 863093 by 21.

On to step 1:
8 divided by 21 is 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 21

Step 2:
21 goes into 86 4 times with a remainder of 2.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
The remainder is 2 after subtracting 84 from 86.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 21

Step 3:
23 divided by 21 is 1 with a remainder of 2.
Write down 1 as next digit of the result. 
Result so far: 41.0
Deduct 21 from 23 and we're left with 2.
Grab the next digit (0) from the dividend, add it to 2, then carry on: 20 / 21

Moving on to step 4:
21 can be fit into 20 0 times, resulting in a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 410.0
Subtracting 0 from 20 leaves us with 20.
Grab the next digit (9) from the dividend, add it to 20, then carry on: 209 / 21

Step 5:
When dividing 209 by 21, we get 9 with a remainder of 20.
Write down 9 as next digit of the result. 
Result so far: 4109.0
If we subtract 189 from 209, we get 20.
Grab the next digit (3) from the dividend, add it to 20, then carry on: 203 / 21

Going ahead to step 6:
When dividing 203 by 21, we get 9 with a remainder of 14.
The number 9 becomes the next digit in our result. 
Result so far: 41099.0
Deduct 189 from 203 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.

On to step 7:
140 divided by 21 is 6 with a remainder of 14.
Write down 6 as next digit of the result. 
Result so far: 41099.6
The remainder is 14 after subtracting 126 from 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Step 8:
140 divided by 21 is 6 with a remainder of 14.
Write down 6 as next digit of the result. 
Result so far: 41099.66
If we subtract 126 from 140, 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.

The final result is 41099.66 with a remainder of 0.014.