We're dividing 51393 by 21 
Our goal is to divide 51393 by 21.

Going ahead to step 1:
When dividing 5 by 21, we get 0 with a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 21

Step 2:
21 goes into 51 2 times with a remainder of 9.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Deduct 42 from 51 and we're left with 9.
Append the next digit (3) from the dividend to 9 and continue with: 93 / 21

On to step 3:
If we divide 93 by 21, we get 4 and a remainder of 9.
The number 4 becomes the next digit in our result. 
Result so far: 24.0
The remainder is 9 after subtracting 84 from 93.
Take the next digit (9) from the dividend and append it to 9, then repeat: 99 / 21

Step 4:
The number 21 fits into 99 4 times, leaving a remainder of 15.
Put 4 as the next digit of the answer. 
Result so far: 244.0
Subtract 84 from 99 to get 15.
Fetch the next digit (3) from the dividend, attach it to 15 and continue: 153 / 21

Let's proceed to step 5:
21 can be fit into 153 7 times, resulting in a remainder of 6.
Use 7 as the next digit of our solution. 
Result so far: 2447.0
Deduct 147 from 153 and we're left 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.

Moving on to step 6:
If we divide 60 by 21, we get 2 and a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 2447.2
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.

Going ahead to step 7:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 2447.28
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 8:
When dividing 120 by 21, we get 5 with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 2447.285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 9:
When dividing 150 by 21, we get 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 2447.2857
Deduct 147 from 150 and we're left with 3.
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 10:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 2447.28571
The remainder is 9 after subtracting 21 from 30.
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 11:
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: 2447.285714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 12:
21 goes into 60 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 2447.2857142
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.

On to step 13:
The number 21 fits into 180 8 times, leaving a remainder of 12.
The next digit of our result is 8. 
Result so far: 2447.28571428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Our division results in 2447.28571428 with a remaining 1.2e-08.