We look at the division of 72121308 by 90 
Our goal is to divide 72121308 by 90.

Step 1:
90 can be fit into 7 0 times, resulting in a remainder of 7.
The number 0 becomes the next digit in our 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 / 90

On to step 2:
72 divided by 90 is 0 with a remainder of 72.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 72, we get 72.
Grab the next digit (1) from the dividend, add it to 72, then carry on: 721 / 90

Step 3:
If we divide 721 by 90, we get 8 and a remainder of 1.
The number 8 becomes the next digit in our result. 
Result so far: 8.0
Deduct 720 from 721 and we're left with 1.
Fetch the next digit (2) from the dividend, attach it to 1 and continue: 12 / 90

Let's proceed to step 4:
12 divided by 90 is 0 with a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 80.0
The remainder is 12 after subtracting 0 from 12.
Fetch the next digit (1) from the dividend, attach it to 12 and continue: 121 / 90

Step 5:
When dividing 121 by 90, we get 1 with a remainder of 31.
Write down 1 as next digit of the result. 
Result so far: 801.0
Deduct 90 from 121 and we're left with 31.
Take the next digit (3) from the dividend and append it to 31, then repeat: 313 / 90

Going ahead to step 6:
When dividing 313 by 90, we get 3 with a remainder of 43.
The next digit of our result is 3. 
Result so far: 8013.0
If we subtract 270 from 313, we get 43.
Grab the next digit (0) from the dividend, add it to 43, then carry on: 430 / 90

Going ahead to step 7:
When dividing 430 by 90, we get 4 with a remainder of 70.
Put 4 as the next digit of the answer. 
Result so far: 80134.0
Subtracting 360 from 430 leaves us with 70.
Fetch the next digit (8) from the dividend, attach it to 70 and continue: 708 / 90

Advancing to step 8:
The number 90 fits into 708 7 times, leaving a remainder of 78.
Use 7 as the next digit of our solution. 
Result so far: 801347.0
If we subtract 630 from 708, we get 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

On to step 9:
If we divide 780 by 90, we get 8 and a remainder of 60.
Use 8 as the next digit of our solution. 
Result so far: 801347.8
The remainder is 60 after subtracting 720 from 780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Moving on to step 10:
90 goes into 600 6 times with a remainder of 60.
Record the quotient 6 as the next digit in the result. 
Result so far: 801347.86
If we subtract 540 from 600, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Let's proceed to step 11:
600 divided by 90 is 6 with a remainder of 60.
Record the quotient 6 as the next digit in the result. 
Result so far: 801347.866
The remainder is 60 after subtracting 540 from 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

The final result is 801347.866 with a remainder of 0.006.