We divide 639900 by 7
We're looking to find how many times 7 goes into 639900.

Going ahead to step 1:
The number 7 fits into 6 0 times, leaving a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 7

On to step 2:
The number 7 fits into 63 9 times, leaving a remainder of 0.
The number 9 becomes the next digit in our result. 
Result so far: 9.0
The remainder is 0 after subtracting 63 from 63.
Fetch the next digit (9) from the dividend, attach it to 0 and continue: 9 / 7

Going ahead to step 3:
If we divide 9 by 7, we get 1 and a remainder of 2.
Use 1 as the next digit of our solution. 
Result so far: 91.0
Subtract 7 from 9 to get 2.
Append the next digit (9) from the dividend to 2 and continue with: 29 / 7

Going ahead to step 4:
7 goes into 29 4 times with a remainder of 1.
Write down 4 as next digit of the result. 
Result so far: 914.0
Subtract 28 from 29 to get 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 7

Step 5:
When dividing 10 by 7, we get 1 with a remainder of 3.
The next digit of our result is 1. 
Result so far: 9141.0
Subtract 7 from 10 to get 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 7

Advancing to step 6:
If we divide 30 by 7, we get 4 and a remainder of 2.
The next digit of our result is 4. 
Result so far: 91414.0
If we subtract 28 from 30, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 7:
When dividing 20 by 7, we get 2 with a remainder of 6.
Use 2 as the next digit of our solution. 
Result so far: 91414.2
Subtracting 14 from 20 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 8:
The number 7 fits into 60 8 times, leaving a remainder of 4.
Write down 8 as next digit of the result. 
Result so far: 91414.28
Subtract 56 from 60 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 9:
When dividing 40 by 7, we get 5 with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 91414.285
If we subtract 35 from 40, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 10:
If we divide 50 by 7, we get 7 and a remainder of 1.
The number 7 becomes the next digit in our result. 
Result so far: 91414.2857
Subtract 49 from 50 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 11:
If we divide 10 by 7, we get 1 and a remainder of 3.
The number 1 becomes the next digit in our result. 
Result so far: 91414.28571
Deduct 7 from 10 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 12:
The number 7 fits into 30 4 times, leaving a remainder of 2.
The number 4 becomes the next digit in our result. 
Result so far: 91414.285714
Subtracting 28 from 30 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 13:
20 divided by 7 is 2 with a remainder of 6.
Put 2 as the next digit of the answer. 
Result so far: 91414.2857142
Subtracting 14 from 20 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 14:
If we divide 60 by 7, we get 8 and a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 91414.28571428
If we subtract 56 from 60, we 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.

The final result is 91414.28571428 with a remainder of 4e-09.