3951907 ÷ 639 
We want to divide 3951907 by 639.

Moving on to step 1:
If we divide 3 by 639, we get 0 and a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 639

Going ahead to step 2:
639 can be fit into 39 0 times, resulting in a remainder of 39.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 39, we get 39.
Grab the next digit (5) from the dividend, add it to 39, then carry on: 395 / 639

On to step 3:
639 can be fit into 395 0 times, resulting in a remainder of 395.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 395, we get 395.
Take the next digit (1) from the dividend and append it to 395, then repeat: 3951 / 639

Let's proceed to step 4:
639 goes into 3951 6 times with a remainder of 117.
Put 6 as the next digit of the answer. 
Result so far: 6.0
If we subtract 3834 from 3951, we get 117.
Take the next digit (9) from the dividend and append it to 117, then repeat: 1179 / 639

Going ahead to step 5:
If we divide 1179 by 639, we get 1 and a remainder of 540.
The next digit of our result is 1. 
Result so far: 61.0
The remainder is 540 after subtracting 639 from 1179.
Bring next digit (0) of the dividend behind the 540 and repeat the process: 5400 / 639

Going ahead to step 6:
639 can be fit into 5400 8 times, resulting in a remainder of 288.
Write down 8 as next digit of the result. 
Result so far: 618.0
The remainder is 288 after subtracting 5112 from 5400.
Fetch the next digit (7) from the dividend, attach it to 288 and continue: 2887 / 639

On to step 7:
When dividing 2887 by 639, we get 4 with a remainder of 331.
Use 4 as the next digit of our solution. 
Result so far: 6184.0
If we take 2556 away from 2887, we end up with 331.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3310, and continue the process.

Step 8:
3310 divided by 639 is 5 with a remainder of 115.
Write down 5 as next digit of the result. 
Result so far: 6184.5
Deduct 3195 from 3310 and we're left with 115.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1150, and continue the process.

Moving on to step 9:
If we divide 1150 by 639, we get 1 and a remainder of 511.
The next digit of our result is 1. 
Result so far: 6184.51
The remainder is 511 after subtracting 639 from 1150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5110, and continue the process.

Step 10:
If we divide 5110 by 639, we get 7 and a remainder of 637.
The next digit of our result is 7. 
Result so far: 6184.517
Deduct 4473 from 5110 and we're left with 637.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6370, and continue the process.

Let's proceed to step 11:
6370 divided by 639 is 9 with a remainder of 619.
Record the quotient 9 as the next digit in the result. 
Result so far: 6184.5179
The remainder is 619 after subtracting 5751 from 6370.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6190, and continue the process.

Step 12:
639 goes into 6190 9 times with a remainder of 439.
The number 9 becomes the next digit in our result. 
Result so far: 6184.51799
If we subtract 5751 from 6190, we get 439.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4390, and continue the process.

Our division results in 6184.51799 with a remaining 0.000439.