We're dividing 720581 by 21 
We want to figure out the number of times 720581 can be divided by 21.

On to step 1:
When dividing 7 by 21, we get 0 with a remainder of 7.
Write down 0 as next digit of 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 / 21

Step 2:
21 goes into 72 3 times with a remainder of 9.
Write down 3 as next digit of the result. 
Result so far: 3.0
The remainder is 9 after subtracting 63 from 72.
Take the next digit (0) from the dividend and append it to 9, then repeat: 90 / 21

On to step 3:
21 goes into 90 4 times with a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 34.0
If we subtract 84 from 90, we get 6.
Take the next digit (5) from the dividend and append it to 6, then repeat: 65 / 21

Step 4:
21 can be fit into 65 3 times, resulting in a remainder of 2.
The number 3 becomes the next digit in our result. 
Result so far: 343.0
Subtract 63 from 65 to get 2.
Take the next digit (8) from the dividend and append it to 2, then repeat: 28 / 21

Moving on to step 5:
If we divide 28 by 21, we get 1 and a remainder of 7.
Record the quotient 1 as the next digit in the result. 
Result so far: 3431.0
The remainder is 7 after subtracting 21 from 28.
Grab the next digit (1) from the dividend, add it to 7, then carry on: 71 / 21

Moving on to step 6:
21 goes into 71 3 times with a remainder of 8.
Put 3 as the next digit of the answer. 
Result so far: 34313.0
If we subtract 63 from 71, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 7:
21 can be fit into 80 3 times, resulting in a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 34313.3
If we take 63 away from 80, we end up with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

On to step 8:
21 can be fit into 170 8 times, resulting in a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 34313.38
Deduct 168 from 170 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 9:
When dividing 20 by 21, we get 0 with a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 34313.38
Subtract 0 from 20 to 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.

Moving on to step 10:
When dividing 200 by 21, we get 9 with a remainder of 11.
The next digit of our result is 9. 
Result so far: 34313.3809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 11:
110 divided by 21 is 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 34313.38095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 12:
50 divided by 21 is 2 with a remainder of 8.
The next digit of our result is 2. 
Result so far: 34313.380952
Subtracting 42 from 50 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 13:
21 can be fit into 80 3 times, resulting in a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 34313.3809523
Subtracting 63 from 80 leaves us with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 14:
When dividing 170 by 21, we get 8 with a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 34313.38095238
Subtract 168 from 170 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

The final result is 34313.38095238 with a remainder of 2e-09.