643253 ÷ 80 
We want to divide 643253 by 80.

Advancing to step 1:
80 goes into 6 0 times with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 80

Going ahead to step 2:
The number 80 fits into 64 0 times, leaving a remainder of 64.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 64 leaves us with 64.
Take the next digit (3) from the dividend and append it to 64, then repeat: 643 / 80

Going ahead to step 3:
The number 80 fits into 643 8 times, leaving a remainder of 3.
Put 8 as the next digit of the answer. 
Result so far: 8.0
Subtracting 640 from 643 leaves us with 3.
Include the next digit (2) from the dividend after 3, then repeat: 32 / 80

Moving on to step 4:
32 divided by 80 is 0 with a remainder of 32.
Put 0 as the next digit of the answer. 
Result so far: 80.0
If we take 0 away from 32, we end up with 32.
Grab the next digit (5) from the dividend, add it to 32, then carry on: 325 / 80

Going ahead to step 5:
The number 80 fits into 325 4 times, leaving a remainder of 5.
Put 4 as the next digit of the answer. 
Result so far: 804.0
Deduct 320 from 325 and we're left with 5.
Append the next digit (3) from the dividend to 5 and continue with: 53 / 80

Moving on to step 6:
80 goes into 53 0 times with a remainder of 53.
Put 0 as the next digit of the answer. 
Result so far: 8040.0
If we subtract 0 from 53, we get 53.
Since there are no more digits in the dividend, we add a zero to the remainder making it 530, and continue the process.

Let's proceed to step 7:
If we divide 530 by 80, we get 6 and a remainder of 50.
Write down 6 as next digit of the result. 
Result so far: 8040.6
Subtract 480 from 530 to get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 8:
The number 80 fits into 500 6 times, leaving a remainder of 20.
The number 6 becomes the next digit in our result. 
Result so far: 8040.66
If we subtract 480 from 500, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Our division results in 8040.66 with a remaining 0.02.