831798 divided by 21 
Our goal is to divide 831798 by 21.

Step 1:
8 divided by 21 is 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Include the next digit (3) from the dividend after 8, then repeat: 83 / 21

On to step 2:
21 goes into 83 3 times with a remainder of 20.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
If we subtract 63 from 83, we get 20.
Append the next digit (1) from the dividend to 20 and continue with: 201 / 21

Going ahead to step 3:
201 divided by 21 is 9 with a remainder of 12.
The number 9 becomes the next digit in our result. 
Result so far: 39.0
Deduct 189 from 201 and we're left with 12.
Bring next digit (7) of the dividend behind the 12 and repeat the process: 127 / 21

Going ahead to step 4:
When dividing 127 by 21, we get 6 with a remainder of 1.
Write down 6 as next digit of the result. 
Result so far: 396.0
Subtract 126 from 127 to get 1.
Fetch the next digit (9) from the dividend, attach it to 1 and continue: 19 / 21

Let's proceed to step 5:
21 can be fit into 19 0 times, resulting in a remainder of 19.
Put 0 as the next digit of the answer. 
Result so far: 3960.0
If we take 0 away from 19, we end up with 19.
Grab the next digit (8) from the dividend, add it to 19, then carry on: 198 / 21

On to step 6:
When dividing 198 by 21, we get 9 with a remainder of 9.
Put 9 as the next digit of the answer. 
Result so far: 39609.0
If we subtract 189 from 198, we get 9.
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 7:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 39609.4
Subtracting 84 from 90 leaves us 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.

Step 8:
When dividing 60 by 21, we get 2 with a remainder of 18.
The next digit of our result is 2. 
Result so far: 39609.42
Subtract 42 from 60 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 9:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 39609.428
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 10:
120 divided by 21 is 5 with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 39609.4285
If we take 105 away from 120, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 11:
150 divided by 21 is 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 39609.42857
The remainder is 3 after subtracting 147 from 150.
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 12:
If we divide 30 by 21, we get 1 and a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 39609.428571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 13:
If we divide 90 by 21, we get 4 and a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 39609.4285714
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 14:
21 can be fit into 60 2 times, resulting in a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 39609.42857142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Our division results in 39609.42857142 with a remaining 1.8e-08.