72108958 ÷ 639 
We want to figure out the number of times 72108958 can be divided by 639.

Step 1:
If we divide 7 by 639, we get 0 and a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 7 to get 7.
Include the next digit (2) from the dividend after 7, then repeat: 72 / 639

On to step 2:
If we divide 72 by 639, we get 0 and a remainder of 72.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 72 leaves us with 72.
Include the next digit (1) from the dividend after 72, then repeat: 721 / 639

On to step 3:
721 divided by 639 is 1 with a remainder of 82.
The next digit of our result is 1. 
Result so far: 1.0
If we take 639 away from 721, we end up with 82.
Append the next digit (0) from the dividend to 82 and continue with: 820 / 639

Moving on to step 4:
639 can be fit into 820 1 times, resulting in a remainder of 181.
Use 1 as the next digit of our solution. 
Result so far: 11.0
Subtracting 639 from 820 leaves us with 181.
Take the next digit (8) from the dividend and append it to 181, then repeat: 1818 / 639

Moving on to step 5:
639 goes into 1818 2 times with a remainder of 540.
Put 2 as the next digit of the answer. 
Result so far: 112.0
If we take 1278 away from 1818, we end up with 540.
Grab the next digit (9) from the dividend, add it to 540, then carry on: 5409 / 639

On to step 6:
When dividing 5409 by 639, we get 8 with a remainder of 297.
Use 8 as the next digit of our solution. 
Result so far: 1128.0
Deduct 5112 from 5409 and we're left with 297.
Append the next digit (5) from the dividend to 297 and continue with: 2975 / 639

Moving on to step 7:
When dividing 2975 by 639, we get 4 with a remainder of 419.
The next digit of our result is 4. 
Result so far: 11284.0
If we take 2556 away from 2975, we end up with 419.
Append the next digit (8) from the dividend to 419 and continue with: 4198 / 639

Let's proceed to step 8:
639 goes into 4198 6 times with a remainder of 364.
The number 6 becomes the next digit in our result. 
Result so far: 112846.0
Subtract 3834 from 4198 to get 364.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3640, and continue the process.

Let's proceed to step 9:
639 goes into 3640 5 times with a remainder of 445.
The next digit of our result is 5. 
Result so far: 112846.5
The remainder is 445 after subtracting 3195 from 3640.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4450, and continue the process.

On to step 10:
639 goes into 4450 6 times with a remainder of 616.
The next digit of our result is 6. 
Result so far: 112846.56
Subtract 3834 from 4450 to get 616.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6160, and continue the process.

Let's proceed to step 11:
When dividing 6160 by 639, we get 9 with a remainder of 409.
Record the quotient 9 as the next digit in the result. 
Result so far: 112846.569
Subtract 5751 from 6160 to get 409.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4090, and continue the process.

Advancing to step 12:
When dividing 4090 by 639, we get 6 with a remainder of 256.
Write down 6 as next digit of the result. 
Result so far: 112846.5696
Subtracting 3834 from 4090 leaves us with 256.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2560, and continue the process.

Going ahead to step 13:
639 goes into 2560 4 times with a remainder of 4.
The number 4 becomes the next digit in our result. 
Result so far: 112846.56964
Deduct 2556 from 2560 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 14:
When dividing 40 by 639, we get 0 with a remainder of 40.
Write down 0 as next digit of the result. 
Result so far: 112846.56964
The remainder is 40 after subtracting 0 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Advancing to step 15:
If we divide 400 by 639, we get 0 and a remainder of 400.
Use 0 as the next digit of our solution. 
Result so far: 112846.56964
If we subtract 0 from 400, we get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

The final result is 112846.56964 with a remainder of 4e-06.