39915609 ÷ 312 
We want to divide 39915609 by 312.

On to step 1:
When dividing 3 by 312, we get 0 with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 312

On to step 2:
The number 312 fits into 39 0 times, leaving a remainder of 39.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 39 after subtracting 0 from 39.
Append the next digit (9) from the dividend to 39 and continue with: 399 / 312

Moving on to step 3:
312 can be fit into 399 1 times, resulting in a remainder of 87.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtract 312 from 399 to get 87.
Include the next digit (1) from the dividend after 87, then repeat: 871 / 312

Let's proceed to step 4:
312 goes into 871 2 times with a remainder of 247.
Record the quotient 2 as the next digit in the result. 
Result so far: 12.0
Deduct 624 from 871 and we're left with 247.
Bring next digit (5) of the dividend behind the 247 and repeat the process: 2475 / 312

Let's proceed to step 5:
2475 divided by 312 is 7 with a remainder of 291.
Record the quotient 7 as the next digit in the result. 
Result so far: 127.0
If we take 2184 away from 2475, we end up with 291.
Fetch the next digit (6) from the dividend, attach it to 291 and continue: 2916 / 312

Step 6:
When dividing 2916 by 312, we get 9 with a remainder of 108.
Put 9 as the next digit of the answer. 
Result so far: 1279.0
If we take 2808 away from 2916, we end up with 108.
Include the next digit (0) from the dividend after 108, then repeat: 1080 / 312

Let's proceed to step 7:
1080 divided by 312 is 3 with a remainder of 144.
Put 3 as the next digit of the answer. 
Result so far: 12793.0
Deduct 936 from 1080 and we're left with 144.
Append the next digit (9) from the dividend to 144 and continue with: 1449 / 312

Advancing to step 8:
312 can be fit into 1449 4 times, resulting in a remainder of 201.
The next digit of our result is 4. 
Result so far: 127934.0
Subtract 1248 from 1449 to get 201.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2010, and continue the process.

Moving on to step 9:
2010 divided by 312 is 6 with a remainder of 138.
Record the quotient 6 as the next digit in the result. 
Result so far: 127934.6
Subtracting 1872 from 2010 leaves us with 138.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1380, and continue the process.

On to step 10:
1380 divided by 312 is 4 with a remainder of 132.
The number 4 becomes the next digit in our result. 
Result so far: 127934.64
The remainder is 132 after subtracting 1248 from 1380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1320, and continue the process.

Advancing to step 11:
1320 divided by 312 is 4 with a remainder of 72.
Record the quotient 4 as the next digit in the result. 
Result so far: 127934.644
Deduct 1248 from 1320 and we're left with 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Our division results in 127934.644 with a remaining 0.0072.