638568 ÷ 51 
Let's see how many times 51 fits into 638568.

Step 1:
51 goes into 6 0 times with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 51

On to step 2:
The number 51 fits into 63 1 times, leaving a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 51 from 63 leaves us with 12.
Append the next digit (8) from the dividend to 12 and continue with: 128 / 51

On to step 3:
51 can be fit into 128 2 times, resulting in a remainder of 26.
Use 2 as the next digit of our solution. 
Result so far: 12.0
Subtract 102 from 128 to get 26.
Grab the next digit (5) from the dividend, add it to 26, then carry on: 265 / 51

Advancing to step 4:
The number 51 fits into 265 5 times, leaving a remainder of 10.
Write down 5 as next digit of the result. 
Result so far: 125.0
The remainder is 10 after subtracting 255 from 265.
Take the next digit (6) from the dividend and append it to 10, then repeat: 106 / 51

Step 5:
106 divided by 51 is 2 with a remainder of 4.
The next digit of our result is 2. 
Result so far: 1252.0
Deduct 102 from 106 and we're left with 4.
Include the next digit (8) from the dividend after 4, then repeat: 48 / 51

Going ahead to step 6:
51 goes into 48 0 times with a remainder of 48.
Use 0 as the next digit of our solution. 
Result so far: 12520.0
If we subtract 0 from 48, we get 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Going ahead to step 7:
When dividing 480 by 51, we get 9 with a remainder of 21.
The number 9 becomes the next digit in our result. 
Result so far: 12520.9
The remainder is 21 after subtracting 459 from 480.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Moving on to step 8:
The number 51 fits into 210 4 times, leaving a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 12520.94
If we take 204 away from 210, we end up 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.

Let's proceed to step 9:
If we divide 60 by 51, we get 1 and a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 12520.941
Deduct 51 from 60 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.

On to step 10:
51 goes into 90 1 times with a remainder of 39.
The next digit of our result is 1. 
Result so far: 12520.9411
Subtract 51 from 90 to get 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

The quotient of the division is 12520.9411, and the remainder is 0.00039.