We're dividing 257396 by 21 
Our goal is to divide 257396 by 21.

Step 1:
The number 21 fits into 2 0 times, leaving a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Fetch the next digit (5) from the dividend, attach it to 2 and continue: 25 / 21

On to step 2:
21 goes into 25 1 times with a remainder of 4.
Put 1 as the next digit of the answer. 
Result so far: 1.0
The remainder is 4 after subtracting 21 from 25.
Fetch the next digit (7) from the dividend, attach it to 4 and continue: 47 / 21

Advancing to step 3:
47 divided by 21 is 2 with a remainder of 5.
Put 2 as the next digit of the answer. 
Result so far: 12.0
Subtract 42 from 47 to get 5.
Include the next digit (3) from the dividend after 5, then repeat: 53 / 21

Moving on to step 4:
When dividing 53 by 21, we get 2 with a remainder of 11.
Write down 2 as next digit of the result. 
Result so far: 122.0
Deduct 42 from 53 and we're left with 11.
Append the next digit (9) from the dividend to 11 and continue with: 119 / 21

Going ahead to step 5:
When dividing 119 by 21, we get 5 with a remainder of 14.
Record the quotient 5 as the next digit in the result. 
Result so far: 1225.0
Subtract 105 from 119 to get 14.
Take the next digit (6) from the dividend and append it to 14, then repeat: 146 / 21

Let's proceed to step 6:
When dividing 146 by 21, we get 6 with a remainder of 20.
Write down 6 as next digit of the result. 
Result so far: 12256.0
Subtract 126 from 146 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 7:
21 goes into 200 9 times with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 12256.9
The remainder is 11 after subtracting 189 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 8:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 12256.95
Deduct 105 from 110 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 9:
21 goes into 50 2 times with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 12256.952
If we take 42 away from 50, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 10:
When dividing 80 by 21, we get 3 with a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 12256.9523
Deduct 63 from 80 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 11:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 12256.95238
Subtract 168 from 170 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 12:
If we divide 20 by 21, we get 0 and a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 12256.95238
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 13:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 12256.9523809
The remainder is 11 after subtracting 189 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 14:
110 divided by 21 is 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 12256.95238095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Our division results in 12256.95238095 with a remaining 5e-09.