21291238 divided by 391 
Our goal is to divide 21291238 by 391.

On to step 1:
391 can be fit into 2 0 times, resulting in a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Include the next digit (1) from the dividend after 2, then repeat: 21 / 391

Going ahead to step 2:
21 divided by 391 is 0 with a remainder of 21.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 21 after subtracting 0 from 21.
Bring next digit (2) of the dividend behind the 21 and repeat the process: 212 / 391

Going ahead to step 3:
When dividing 212 by 391, we get 0 with a remainder of 212.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 212, we get 212.
Append the next digit (9) from the dividend to 212 and continue with: 2129 / 391

Going ahead to step 4:
391 can be fit into 2129 5 times, resulting in a remainder of 174.
Put 5 as the next digit of the answer. 
Result so far: 5.0
If we subtract 1955 from 2129, we get 174.
Include the next digit (1) from the dividend after 174, then repeat: 1741 / 391

Let's proceed to step 5:
1741 divided by 391 is 4 with a remainder of 177.
The next digit of our result is 4. 
Result so far: 54.0
If we take 1564 away from 1741, we end up with 177.
Fetch the next digit (2) from the dividend, attach it to 177 and continue: 1772 / 391

Moving on to step 6:
1772 divided by 391 is 4 with a remainder of 208.
Record the quotient 4 as the next digit in the result. 
Result so far: 544.0
If we take 1564 away from 1772, we end up with 208.
Include the next digit (3) from the dividend after 208, then repeat: 2083 / 391

Step 7:
If we divide 2083 by 391, we get 5 and a remainder of 128.
The number 5 becomes the next digit in our result. 
Result so far: 5445.0
If we subtract 1955 from 2083, we get 128.
Fetch the next digit (8) from the dividend, attach it to 128 and continue: 1288 / 391

Step 8:
When dividing 1288 by 391, we get 3 with a remainder of 115.
The next digit of our result is 3. 
Result so far: 54453.0
If we take 1173 away from 1288, we end up with 115.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1150, and continue the process.

Moving on to step 9:
391 goes into 1150 2 times with a remainder of 368.
Use 2 as the next digit of our solution. 
Result so far: 54453.2
The remainder is 368 after subtracting 782 from 1150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3680, and continue the process.

Moving on to step 10:
If we divide 3680 by 391, we get 9 and a remainder of 161.
Write down 9 as next digit of the result. 
Result so far: 54453.29
Deduct 3519 from 3680 and we're left with 161.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1610, and continue the process.

Moving on to step 11:
When dividing 1610 by 391, we get 4 with a remainder of 46.
Write down 4 as next digit of the result. 
Result so far: 54453.294
If we subtract 1564 from 1610, we get 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Moving on to step 12:
When dividing 460 by 391, we get 1 with a remainder of 69.
Write down 1 as next digit of the result. 
Result so far: 54453.2941
Deduct 391 from 460 and we're left with 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 690, and continue the process.

Advancing to step 13:
If we divide 690 by 391, we get 1 and a remainder of 299.
Write down 1 as next digit of the result. 
Result so far: 54453.29411
If we subtract 391 from 690, we get 299.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2990, and continue the process.

The final result is 54453.29411 with a remainder of 0.000299.