We divide 639994 by 10
We're looking to find how many times 10 goes into 639994.

Advancing to step 1:
10 can be fit into 6 0 times, resulting in a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 10

Moving on to step 2:
The number 10 fits into 63 6 times, leaving a remainder of 3.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
Subtracting 60 from 63 leaves us with 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 10

Step 3:
10 can be fit into 39 3 times, resulting in a remainder of 9.
The next digit of our result is 3. 
Result so far: 63.0
The remainder is 9 after subtracting 30 from 39.
Fetch the next digit (9) from the dividend, attach it to 9 and continue: 99 / 10

Advancing to step 4:
When dividing 99 by 10, we get 9 with a remainder of 9.
Record the quotient 9 as the next digit in the result. 
Result so far: 639.0
The remainder is 9 after subtracting 90 from 99.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 10

Advancing to step 5:
10 can be fit into 99 9 times, resulting in a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 6399.0
Subtract 90 from 99 to get 9.
Bring next digit (4) of the dividend behind the 9 and repeat the process: 94 / 10

Advancing to step 6:
94 divided by 10 is 9 with a remainder of 4.
Record the quotient 9 as the next digit in the result. 
Result so far: 63999.0
Subtract 90 from 94 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 7:
40 divided by 10 is 4 with a remainder of 0.
Put 4 as the next digit of the answer. 
Result so far: 63999.4
Subtract 40 from 40 to 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.

Let's proceed to step 8:
10 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 63999.4
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 9:
10 can be fit into 0 0 times, resulting in a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 63999.4
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 63999.4 with a remainder of 0.0.