39874857 ÷ 51 
Let's see how many times 51 fits into 39874857.

Going ahead to step 1:
51 can be fit into 3 0 times, resulting in a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Take the next digit (9) from the dividend and append it to 3, then repeat: 39 / 51

Step 2:
If we divide 39 by 51, we get 0 and a remainder of 39.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 39 and we're left with 39.
Append the next digit (8) from the dividend to 39 and continue with: 398 / 51

On to step 3:
51 goes into 398 7 times with a remainder of 41.
The next digit of our result is 7. 
Result so far: 7.0
If we subtract 357 from 398, we get 41.
Include the next digit (7) from the dividend after 41, then repeat: 417 / 51

Going ahead to step 4:
When dividing 417 by 51, we get 8 with a remainder of 9.
Write down 8 as next digit of the result. 
Result so far: 78.0
If we subtract 408 from 417, we get 9.
Fetch the next digit (4) from the dividend, attach it to 9 and continue: 94 / 51

Let's proceed to step 5:
When dividing 94 by 51, we get 1 with a remainder of 43.
Record the quotient 1 as the next digit in the result. 
Result so far: 781.0
If we subtract 51 from 94, we get 43.
Include the next digit (8) from the dividend after 43, then repeat: 438 / 51

Moving on to step 6:
When dividing 438 by 51, we get 8 with a remainder of 30.
The next digit of our result is 8. 
Result so far: 7818.0
Subtract 408 from 438 to get 30.
Grab the next digit (5) from the dividend, add it to 30, then carry on: 305 / 51

Going ahead to step 7:
51 goes into 305 5 times with a remainder of 50.
Write down 5 as next digit of the result. 
Result so far: 78185.0
Subtracting 255 from 305 leaves us with 50.
Append the next digit (7) from the dividend to 50 and continue with: 507 / 51

Moving on to step 8:
If we divide 507 by 51, we get 9 and a remainder of 48.
Write down 9 as next digit of the result. 
Result so far: 781859.0
Subtracting 459 from 507 leaves us with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

On to step 9:
480 divided by 51 is 9 with a remainder of 21.
Use 9 as the next digit of our solution. 
Result so far: 781859.9
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.

Step 10:
51 can be fit into 210 4 times, resulting in a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 781859.94
Deduct 204 from 210 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.

Going ahead to step 11:
The number 51 fits into 60 1 times, leaving a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 781859.941
Subtracting 51 from 60 leaves us 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 12:
When dividing 90 by 51, we get 1 with a remainder of 39.
The number 1 becomes the next digit in our result. 
Result so far: 781859.9411
If we take 51 away from 90, we end up with 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 final result is 781859.9411 with a remainder of 0.00039.