We're dividing 309391 by 80 
We want to figure out the number of times 309391 can be divided by 80.

Let's proceed to step 1:
When dividing 3 by 80, we get 0 with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Take the next digit (0) from the dividend and append it to 3, then repeat: 30 / 80

Step 2:
When dividing 30 by 80, we get 0 with a remainder of 30.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 30 after subtracting 0 from 30.
Include the next digit (9) from the dividend after 30, then repeat: 309 / 80

On to step 3:
80 goes into 309 3 times with a remainder of 69.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
Deduct 240 from 309 and we're left with 69.
Include the next digit (3) from the dividend after 69, then repeat: 693 / 80

On to step 4:
693 divided by 80 is 8 with a remainder of 53.
Record the quotient 8 as the next digit in the result. 
Result so far: 38.0
Subtract 640 from 693 to get 53.
Grab the next digit (9) from the dividend, add it to 53, then carry on: 539 / 80

Advancing to step 5:
539 divided by 80 is 6 with a remainder of 59.
Put 6 as the next digit of the answer. 
Result so far: 386.0
If we subtract 480 from 539, we get 59.
Take the next digit (1) from the dividend and append it to 59, then repeat: 591 / 80

Going ahead to step 6:
591 divided by 80 is 7 with a remainder of 31.
The number 7 becomes the next digit in our result. 
Result so far: 3867.0
Subtracting 560 from 591 leaves us with 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Moving on to step 7:
The number 80 fits into 310 3 times, leaving a remainder of 70.
The number 3 becomes the next digit in our result. 
Result so far: 3867.3
Subtract 240 from 310 to get 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Moving on to step 8:
When dividing 700 by 80, we get 8 with a remainder of 60.
The number 8 becomes the next digit in our result. 
Result so far: 3867.38
Subtracting 640 from 700 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Going ahead to step 9:
600 divided by 80 is 7 with a remainder of 40.
Record the quotient 7 as the next digit in the result. 
Result so far: 3867.387
Subtracting 560 from 600 leaves us with 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 10:
The number 80 fits into 400 5 times, leaving a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 3867.3875
The remainder is 0 after subtracting 400 from 400.
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 11:
80 goes into 0 0 times with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 3867.3875
Subtracting 0 from 0 leaves us with 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 12:
80 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 3867.3875
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 quotient of the division is 3867.3875, and the remainder is 0.0.