We're dividing 51807217 by 21 
Our goal is to divide 51807217 by 21.

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.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 21

Let's proceed to step 2:
When dividing 51 by 21, we get 2 with a remainder of 9.
The next digit of our result is 2. 
Result so far: 2.0
If we subtract 42 from 51, we get 9.
Append the next digit (8) from the dividend to 9 and continue with: 98 / 21

Let's proceed to step 3:
21 can be fit into 98 4 times, resulting in a remainder of 14.
Record the quotient 4 as the next digit in the result. 
Result so far: 24.0
If we take 84 away from 98, we end up with 14.
Bring next digit (0) of the dividend behind the 14 and repeat the process: 140 / 21

Step 4:
21 can be fit into 140 6 times, resulting in a remainder of 14.
The number 6 becomes the next digit in our result. 
Result so far: 246.0
Subtract 126 from 140 to get 14.
Bring next digit (7) of the dividend behind the 14 and repeat the process: 147 / 21

Step 5:
21 can be fit into 147 7 times, resulting in a remainder of 0.
Write down 7 as next digit of the result. 
Result so far: 2467.0
Deduct 147 from 147 and we're left with 0.
Include the next digit (2) from the dividend after 0, then repeat: 2 / 21

Advancing to step 6:
21 goes into 2 0 times with a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 24670.0
The remainder is 2 after subtracting 0 from 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 21

Moving on to step 7:
21 goes into 21 1 times with a remainder of 0.
Put 1 as the next digit of the answer. 
Result so far: 246701.0
Subtract 21 from 21 to get 0.
Append the next digit (7) from the dividend to 0 and continue with: 7 / 21

Advancing to step 8:
21 can be fit into 7 0 times, resulting in a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 2467010.0
Subtracting 0 from 7 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Let's proceed to step 9:
21 goes into 70 3 times with a remainder of 7.
Record the quotient 3 as the next digit in the result. 
Result so far: 2467010.3
Subtract 63 from 70 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 10:
If we divide 70 by 21, we get 3 and a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 2467010.33
If we take 63 away from 70, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Our division results in 2467010.33 with a remaining 0.007.