We're dividing 639870 by 2 
We're looking to find how many times 2 goes into 639870.

Moving on to step 1:
2 goes into 6 3 times with a remainder of 0.
The next digit of our result is 3. 
Result so far: 3.0
Subtract 6 from 6 to get 0.
Include the next digit (3) from the dividend after 0, then repeat: 3 / 2

Step 2:
If we divide 3 by 2, we get 1 and a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 31.0
Subtract 2 from 3 to get 1.
Grab the next digit (9) from the dividend, add it to 1, then carry on: 19 / 2

On to step 3:
2 goes into 19 9 times with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 319.0
If we take 18 away from 19, we end up with 1.
Bring next digit (8) of the dividend behind the 1 and repeat the process: 18 / 2

Step 4:
If we divide 18 by 2, we get 9 and a remainder of 0.
Write down 9 as next digit of the result. 
Result so far: 3199.0
If we subtract 18 from 18, we get 0.
Fetch the next digit (7) from the dividend, attach it to 0 and continue: 7 / 2

Moving on to step 5:
When dividing 7 by 2, we get 3 with a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 31993.0
Deduct 6 from 7 and we're left with 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 2

On to step 6:
If we divide 10 by 2, we get 5 and a remainder of 0.
The next digit of our result is 5. 
Result so far: 319935.0
Deduct 10 from 10 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 7:
The number 2 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 319935.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
If we divide 0 by 2, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 319935.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 319935.0 with a remainder of 0.0.