721584 ÷ 80 
We're looking to find how many times 80 goes into 721584.

Advancing to step 1:
If we divide 7 by 80, we get 0 and a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Grab the next digit (2) from the dividend, add it to 7, then carry on: 72 / 80

Going ahead to step 2:
The number 80 fits into 72 0 times, leaving a remainder of 72.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 72, we end up with 72.
Take the next digit (1) from the dividend and append it to 72, then repeat: 721 / 80

Let's proceed to step 3:
When dividing 721 by 80, we get 9 with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 9.0
Subtract 720 from 721 to get 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 80

Moving on to step 4:
15 divided by 80 is 0 with a remainder of 15.
The next digit of our result is 0. 
Result so far: 90.0
Deduct 0 from 15 and we're left with 15.
Bring next digit (8) of the dividend behind the 15 and repeat the process: 158 / 80

On to step 5:
The number 80 fits into 158 1 times, leaving a remainder of 78.
Use 1 as the next digit of our solution. 
Result so far: 901.0
Subtracting 80 from 158 leaves us with 78.
Fetch the next digit (4) from the dividend, attach it to 78 and continue: 784 / 80

Let's proceed to step 6:
The number 80 fits into 784 9 times, leaving a remainder of 64.
Write down 9 as next digit of the result. 
Result so far: 9019.0
Subtract 720 from 784 to get 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Moving on to step 7:
80 can be fit into 640 8 times, resulting in a remainder of 0.
Record the quotient 8 as the next digit in the result. 
Result so far: 9019.8
If we take 640 away from 640, we end up 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:
80 can be fit into 0 0 times, resulting in a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 9019.8
Deduct 0 from 0 and we're left 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.

Going ahead to step 9:
80 goes into 0 0 times with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 9019.8
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 final result is 9019.8 with a remainder of 0.0.