393440 ÷ 80 
We want to figure out the number of times 393440 can be divided by 80.

On to step 1:
If we divide 3 by 80, we get 0 and a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 80

Advancing to step 2:
The number 80 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
Subtracting 0 from 39 leaves us with 39.
Grab the next digit (3) from the dividend, add it to 39, then carry on: 393 / 80

Let's proceed to step 3:
If we divide 393 by 80, we get 4 and a remainder of 73.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Subtracting 320 from 393 leaves us with 73.
Take the next digit (4) from the dividend and append it to 73, then repeat: 734 / 80

On to step 4:
The number 80 fits into 734 9 times, leaving a remainder of 14.
Put 9 as the next digit of the answer. 
Result so far: 49.0
Deduct 720 from 734 and we're left with 14.
Grab the next digit (4) from the dividend, add it to 14, then carry on: 144 / 80

Step 5:
If we divide 144 by 80, we get 1 and a remainder of 64.
Use 1 as the next digit of our solution. 
Result so far: 491.0
If we take 80 away from 144, we end up with 64.
Append the next digit (0) from the dividend to 64 and continue with: 640 / 80

On to step 6:
640 divided by 80 is 8 with a remainder of 0.
Use 8 as the next digit of our solution. 
Result so far: 4918.0
Subtract 640 from 640 to 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.

Going ahead to step 7:
If we divide 0 by 80, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 4918.0
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.

Step 8:
The number 80 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 4918.0
Subtract 0 from 0 to 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.

After the division, we end up with 4918.0 and a remainder of 0.0.