We look at the division of 331191 by 21 
Let's see how many times 21 fits into 331191.

Going ahead to step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Fetch the next digit (3) from the dividend, attach it to 3 and continue: 33 / 21

On to step 2:
When dividing 33 by 21, we get 1 with a remainder of 12.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtract 21 from 33 to get 12.
Take the next digit (1) from the dividend and append it to 12, then repeat: 121 / 21

Moving on to step 3:
If we divide 121 by 21, we get 5 and a remainder of 16.
Write down 5 as next digit of the result. 
Result so far: 15.0
Subtract 105 from 121 to get 16.
Take the next digit (1) from the dividend and append it to 16, then repeat: 161 / 21

Step 4:
If we divide 161 by 21, we get 7 and a remainder of 14.
The number 7 becomes the next digit in our result. 
Result so far: 157.0
If we subtract 147 from 161, we get 14.
Take the next digit (9) from the dividend and append it to 14, then repeat: 149 / 21

Moving on to step 5:
21 can be fit into 149 7 times, resulting in a remainder of 2.
Write down 7 as next digit of the result. 
Result so far: 1577.0
Subtract 147 from 149 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 21

Moving on to step 6:
21 divided by 21 is 1 with a remainder of 0.
Use 1 as the next digit of our solution. 
Result so far: 15771.0
Subtract 21 from 21 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 7:
The number 21 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 15771.0
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 8:
21 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 15771.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 15771.0 with a remaining 0.0.