639100 ÷ 99 
We want to divide 639100 by 99.

On to step 1:
99 goes into 6 0 times with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Fetch the next digit (3) from the dividend, attach it to 6 and continue: 63 / 99

On to step 2:
If we divide 63 by 99, we get 0 and a remainder of 63.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 63 and we're left with 63.
Fetch the next digit (9) from the dividend, attach it to 63 and continue: 639 / 99

Let's proceed to step 3:
If we divide 639 by 99, we get 6 and a remainder of 45.
The next digit of our result is 6. 
Result so far: 6.0
If we subtract 594 from 639, we get 45.
Bring next digit (1) of the dividend behind the 45 and repeat the process: 451 / 99

Advancing to step 4:
451 divided by 99 is 4 with a remainder of 55.
The number 4 becomes the next digit in our result. 
Result so far: 64.0
If we subtract 396 from 451, we get 55.
Fetch the next digit (0) from the dividend, attach it to 55 and continue: 550 / 99

Let's proceed to step 5:
99 can be fit into 550 5 times, resulting in a remainder of 55.
Write down 5 as next digit of the result. 
Result so far: 645.0
If we subtract 495 from 550, we get 55.
Bring next digit (0) of the dividend behind the 55 and repeat the process: 550 / 99

On to step 6:
550 divided by 99 is 5 with a remainder of 55.
Put 5 as the next digit of the answer. 
Result so far: 6455.0
If we take 495 away from 550, we end up with 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

On to step 7:
99 can be fit into 550 5 times, resulting in a remainder of 55.
The next digit of our result is 5. 
Result so far: 6455.5
Subtracting 495 from 550 leaves us with 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

Step 8:
99 goes into 550 5 times with a remainder of 55.
Put 5 as the next digit of the answer. 
Result so far: 6455.55
Subtracting 495 from 550 leaves us with 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

The final result is 6455.55 with a remainder of 0.055.