721521 divided by 90 
We want to divide 721521 by 90.

Going ahead to step 1:
When dividing 7 by 90, we get 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Include the next digit (2) from the dividend after 7, then repeat: 72 / 90

Going ahead to step 2:
The number 90 fits into 72 0 times, leaving a remainder of 72.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 72 and we're left with 72.
Fetch the next digit (1) from the dividend, attach it to 72 and continue: 721 / 90

Moving on to step 3:
If we divide 721 by 90, we get 8 and a remainder of 1.
Use 8 as the next digit of our solution. 
Result so far: 8.0
Deduct 720 from 721 and we're left with 1.
Append the next digit (5) from the dividend to 1 and continue with: 15 / 90

Let's proceed to step 4:
If we divide 15 by 90, we get 0 and a remainder of 15.
The next digit of our result is 0. 
Result so far: 80.0
Subtract 0 from 15 to get 15.
Append the next digit (2) from the dividend to 15 and continue with: 152 / 90

On to step 5:
90 can be fit into 152 1 times, resulting in a remainder of 62.
Put 1 as the next digit of the answer. 
Result so far: 801.0
The remainder is 62 after subtracting 90 from 152.
Append the next digit (1) from the dividend to 62 and continue with: 621 / 90

Advancing to step 6:
621 divided by 90 is 6 with a remainder of 81.
Write down 6 as next digit of the result. 
Result so far: 8016.0
If we take 540 away from 621, we end up with 81.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

Advancing to step 7:
If we divide 810 by 90, we get 9 and a remainder of 0.
Put 9 as the next digit of the answer. 
Result so far: 8016.9
If we subtract 810 from 810, 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.

Advancing to step 8:
90 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 8016.9
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.

Moving on to step 9:
When dividing 0 by 90, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 8016.9
The remainder is 0 after subtracting 0 from 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 outcome is 8016.9, with a leftover of 0.0.