We look at the division of 51579 by 21 
We're looking to find how many times 21 goes into 51579.

Advancing to step 1:
5 divided by 21 is 0 with a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Fetch the next digit (1) from the dividend, attach it to 5 and continue: 51 / 21

Step 2:
When dividing 51 by 21, we get 2 with a remainder of 9.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtracting 42 from 51 leaves us with 9.
Bring next digit (5) of the dividend behind the 9 and repeat the process: 95 / 21

Moving on to step 3:
21 can be fit into 95 4 times, resulting in a remainder of 11.
Write down 4 as next digit of the result. 
Result so far: 24.0
Subtract 84 from 95 to get 11.
Include the next digit (7) from the dividend after 11, then repeat: 117 / 21

Moving on to step 4:
21 goes into 117 5 times with a remainder of 12.
The next digit of our result is 5. 
Result so far: 245.0
Subtracting 105 from 117 leaves us with 12.
Take the next digit (9) from the dividend and append it to 12, then repeat: 129 / 21

Let's proceed to step 5:
When dividing 129 by 21, we get 6 with a remainder of 3.
The next digit of our result is 6. 
Result so far: 2456.0
The remainder is 3 after subtracting 126 from 129.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 6:
30 divided by 21 is 1 with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 2456.1
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.

Advancing to step 7:
If we divide 90 by 21, we get 4 and a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 2456.14
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.

Let's proceed to step 8:
21 can be fit into 60 2 times, resulting in a remainder of 18.
Put 2 as the next digit of the answer. 
Result so far: 2456.142
Deduct 42 from 60 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 9:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 2456.1428
Subtracting 168 from 180 leaves us 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.

Let's proceed to step 10:
21 can be fit into 120 5 times, resulting in a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 2456.14285
If we subtract 105 from 120, we 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.

Let's proceed to step 11:
21 goes into 150 7 times with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 2456.142857
If we take 147 away from 150, we end up 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.

Step 12:
If we divide 30 by 21, we get 1 and a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 2456.1428571
Deduct 21 from 30 and we're left 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.

Moving on to step 13:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 2456.14285714
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.

The quotient of the division is 2456.14285714, and the remainder is 6e-09.